/*

  * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  */

 /*

  * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved

  * (C) Copyright IBM Corp. 1996 - 1999 - All Rights Reserved

  *

  * The original version of this source code and documentation

  * is copyrighted and owned by Taligent, Inc., a wholly-owned

  * subsidiary of IBM. These materials are provided under terms

  * of a License Agreement between Taligent and Sun. This technology

  * is protected by multiple US and International patents.

  *

  * This notice and attribution to Taligent may not be removed.

  * Taligent is a registered trademark of Taligent, Inc.

  *

  */

 package java.util;

 import java.io.IOException;

 import java.io.InputStream;

 import java.lang.ref.ReferenceQueue;

 import java.lang.ref.SoftReference;

 import java.lang.ref.WeakReference;

 import java.net.JarURLConnection;

 import java.net.URL;

 import java.net.URLConnection;

 import java.security.AccessController;

 import java.security.PrivilegedAction;

 import java.security.PrivilegedActionException;

 import java.security.PrivilegedExceptionAction;

 import java.util.concurrent.ConcurrentHashMap;

 import java.util.concurrent.ConcurrentMap;

 import java.util.jar.JarEntry;

 import sun.util.locale.BaseLocale;

 import sun.util.locale.LocaleObjectCache;

 /**

  *

  * Resource bundles contain locale-specific objects.  When your program needs a

  * locale-specific resource, a <code>String</code> for example, your program can

  * load it from the resource bundle that is appropriate for the current user's

  * locale. In this way, you can write program code that is largely independent

  * of the user's locale isolating most, if not all, of the locale-specific

  * information in resource bundles.

  *

  * <p>

  * This allows you to write programs that can:

  * <UL type=SQUARE>

  * <LI> be easily localized, or translated, into different languages

  * <LI> handle multiple locales at once

  * <LI> be easily modified later to support even more locales

  * </UL>

  *

  * <P>

  * Resource bundles belong to families whose members share a common base

  * name, but whose names also have additional components that identify

  * their locales. For example, the base name of a family of resource

  * bundles might be "MyResources". The family should have a default

  * resource bundle which simply has the same name as its family -

  * "MyResources" - and will be used as the bundle of last resort if a

  * specific locale is not supported. The family can then provide as

  * many locale-specific members as needed, for example a German one

  * named "MyResources_de".

  *

  * <P>

  * Each resource bundle in a family contains the same items, but the items have

  * been translated for the locale represented by that resource bundle.

  * For example, both "MyResources" and "MyResources_de" may have a

  * <code>String</code> that's used on a button for canceling operations.

  * In "MyResources" the <code>String</code> may contain "Cancel" and in

  * "MyResources_de" it may contain "Abbrechen".

  *

  * <P>

  * If there are different resources for different countries, you

  * can make specializations: for example, "MyResources_de_CH" contains objects for

  * the German language (de) in Switzerland (CH). If you want to only

  * modify some of the resources

  * in the specialization, you can do so.

  *

  * <P>

  * When your program needs a locale-specific object, it loads

  * the <code>ResourceBundle</code> class using the

  * {@link #getBundle(java.lang.String, java.util.Locale) getBundle}

  * method:

  * <blockquote>

  * <pre>

  * ResourceBundle myResources =

  *      ResourceBundle.getBundle("MyResources", currentLocale);

  * </pre>

  * </blockquote>

  *

  * <P>

  * Resource bundles contain key/value pairs. The keys uniquely

  * identify a locale-specific object in the bundle. Here's an

  * example of a <code>ListResourceBundle</code> that contains

  * two key/value pairs:

  * <blockquote>

  * <pre>

  * public class MyResources extends ListResourceBundle {

  *     protected Object[][] getContents() {

  *         return new Object[][] {

  *             // LOCALIZE THE SECOND STRING OF EACH ARRAY (e.g., "OK")

  *             {"OkKey", "OK"},

  *             {"CancelKey", "Cancel"},

  *             // END OF MATERIAL TO LOCALIZE

  *        };

  *     }

  * }

  * </pre>

  * </blockquote>

  * Keys are always <code>String</code>s.

  * In this example, the keys are "OkKey" and "CancelKey".

  * In the above example, the values

  * are also <code>String</code>s--"OK" and "Cancel"--but

  * they don't have to be. The values can be any type of object.

  *

  * <P>

  * You retrieve an object from resource bundle using the appropriate

  * getter method. Because "OkKey" and "CancelKey"

  * are both strings, you would use <code>getString</code> to retrieve them:

  * <blockquote>

  * <pre>

  * button1 = new Button(myResources.getString("OkKey"));

  * button2 = new Button(myResources.getString("CancelKey"));

  * </pre>

  * </blockquote>

  * The getter methods all require the key as an argument and return

  * the object if found. If the object is not found, the getter method

  * throws a <code>MissingResourceException</code>.

  *

  * <P>

  * Besides <code>getString</code>, <code>ResourceBundle</code> also provides

  * a method for getting string arrays, <code>getStringArray</code>,

  * as well as a generic <code>getObject</code> method for any other

  * type of object. When using <code>getObject</code>, you'll

  * have to cast the result to the appropriate type. For example:

  * <blockquote>

  * <pre>

  * int[] myIntegers = (int[]) myResources.getObject("intList");

  * </pre>

  * </blockquote>

  *

  * <P>

  * The Java Platform provides two subclasses of <code>ResourceBundle</code>,

  * <code>ListResourceBundle</code> and <code>PropertyResourceBundle</code>,

  * that provide a fairly simple way to create resources.

  * As you saw briefly in a previous example, <code>ListResourceBundle</code>

  * manages its resource as a list of key/value pairs.

  * <code>PropertyResourceBundle</code> uses a properties file to manage

  * its resources.

  *

  * <p>

  * If <code>ListResourceBundle</code> or <code>PropertyResourceBundle</code>

  * do not suit your needs, you can write your own <code>ResourceBundle</code>

  * subclass.  Your subclasses must override two methods: <code>handleGetObject</code>

  * and <code>getKeys()</code>.

  *

  * <h4>ResourceBundle.Control</h4>

  *

  * The {@link ResourceBundle.Control} class provides information necessary

  * to perform the bundle loading process by the <code>getBundle</code>

  * factory methods that take a <code>ResourceBundle.Control</code>

  * instance. You can implement your own subclass in order to enable

  * non-standard resource bundle formats, change the search strategy, or

  * define caching parameters. Refer to the descriptions of the class and the

  * {@link #getBundle(String, Locale, ClassLoader, Control) getBundle}

  * factory method for details.

  *

  * <h4>Cache Management</h4>

  *

  * Resource bundle instances created by the <code>getBundle</code> factory

  * methods are cached by default, and the factory methods return the same

  * resource bundle instance multiple times if it has been

  * cached. <code>getBundle</code> clients may clear the cache, manage the

  * lifetime of cached resource bundle instances using time-to-live values,

  * or specify not to cache resource bundle instances. Refer to the

  * descriptions of the {@linkplain #getBundle(String, Locale, ClassLoader,

  * Control) <code>getBundle</code> factory method}, {@link

  * #clearCache(ClassLoader) clearCache}, {@link

  * Control#getTimeToLive(String, Locale)

  * ResourceBundle.Control.getTimeToLive}, and {@link

  * Control#needsReload(String, Locale, String, ClassLoader, ResourceBundle,

  * long) ResourceBundle.Control.needsReload} for details.

  *

  * <h4>Example</h4>

  *

  * The following is a very simple example of a <code>ResourceBundle</code>

  * subclass, <code>MyResources</code>, that manages two resources (for a larger number of

  * resources you would probably use a <code>Map</code>).

  * Notice that you don't need to supply a value if

  * a "parent-level" <code>ResourceBundle</code> handles the same

  * key with the same value (as for the okKey below).

  * <blockquote>

  * <pre>

  * // default (English language, United States)

  * public class MyResources extends ResourceBundle {

  *     public Object handleGetObject(String key) {

  *         if (key.equals("okKey")) return "Ok";

  *         if (key.equals("cancelKey")) return "Cancel";

  *         return null;

  *     }

  *

  *     public Enumeration<String> getKeys() {

  *         return Collections.enumeration(keySet());

  *     }

  *

  *     // Overrides handleKeySet() so that the getKeys() implementation

  *     // can rely on the keySet() value.

  *     protected Set<String> handleKeySet() {

  *         return new HashSet<String>(Arrays.asList("okKey", "cancelKey"));

  *     }

  * }

  *

  * // German language

  * public class MyResources_de extends MyResources {

  *     public Object handleGetObject(String key) {

  *         // don't need okKey, since parent level handles it.

  *         if (key.equals("cancelKey")) return "Abbrechen";

  *         return null;

  *     }

  *

  *     protected Set<String> handleKeySet() {

  *         return new HashSet<String>(Arrays.asList("cancelKey"));

  *     }

  * }

  * </pre>

  * </blockquote>

  * You do not have to restrict yourself to using a single family of

  * <code>ResourceBundle</code>s. For example, you could have a set of bundles for

  * exception messages, <code>ExceptionResources</code>

  * (<code>ExceptionResources_fr</code>, <code>ExceptionResources_de</code>, ...),

  * and one for widgets, <code>WidgetResource</code> (<code>WidgetResources_fr</code>,

  * <code>WidgetResources_de</code>, ...); breaking up the resources however you like.

  *

  * @see ListResourceBundle

  * @see PropertyResourceBundle

  * @see MissingResourceException

  * @since JDK1.1

  */

 public abstract class ResourceBundle {

     /** initial size of the bundle cache */

     private static final int INITIAL_CACHE_SIZE = 32;

     /** constant indicating that no resource bundle exists */

     private static final ResourceBundle NONEXISTENT_BUNDLE = new ResourceBundle() {

             public Enumeration<String> getKeys() { return null; }

             protected Object handleGetObject(String key) { return null; }

             public String toString() { return "NONEXISTENT_BUNDLE"; }

         };

     /**

      * The cache is a map from cache keys (with bundle base name, locale, and

      * class loader) to either a resource bundle or NONEXISTENT_BUNDLE wrapped by a

      * BundleReference.

      *

      * The cache is a ConcurrentMap, allowing the cache to be searched

      * concurrently by multiple threads.  This will also allow the cache keys

      * to be reclaimed along with the ClassLoaders they reference.

      *

      * This variable would be better named "cache", but we keep the old

      * name for compatibility with some workarounds for bug 4212439.

      */

     private static final ConcurrentMap<CacheKey, BundleReference> cacheList

         = new ConcurrentHashMap<>(INITIAL_CACHE_SIZE);

     /**

      * Queue for reference objects referring to class loaders or bundles.

      */

     private static final ReferenceQueue referenceQueue = new ReferenceQueue();

     /**

      * The parent bundle of this bundle.

      * The parent bundle is searched by {@link #getObject getObject}

      * when this bundle does not contain a particular resource.

      */

     protected ResourceBundle parent = null;

     /**

      * The locale for this bundle.

      */

     private Locale locale = null;

     /**

      * The base bundle name for this bundle.

      */

     private String name;

     /**

      * The flag indicating this bundle has expired in the cache.

      */

     private volatile boolean expired;

     /**

      * The back link to the cache key. null if this bundle isn't in

      * the cache (yet) or has expired.

      */

     private volatile CacheKey cacheKey;

     /**

      * A Set of the keys contained only in this ResourceBundle.

      */

     private volatile Set<String> keySet;

     /**

      * Sole constructor.  (For invocation by subclass constructors, typically

      * implicit.)

      */

     public ResourceBundle() {

     }

     /**

      * Gets a string for the given key from this resource bundle or one of its parents.

      * Calling this method is equivalent to calling

      * <blockquote>

      * <code>(String) {@link #getObject(java.lang.String) getObject}(key)</code>.

      * </blockquote>

      *

      * @param key the key for the desired string

      * @exception NullPointerException if <code>key</code> is <code>null</code>

      * @exception MissingResourceException if no object for the given key can be found

      * @exception ClassCastException if the object found for the given key is not a string

      * @return the string for the given key

      */

     public final String getString(String key) {

         return (String) getObject(key);

     }

     /**

      * Gets a string array for the given key from this resource bundle or one of its parents.

      * Calling this method is equivalent to calling

      * <blockquote>

      * <code>(String[]) {@link #getObject(java.lang.String) getObject}(key)</code>.

      * </blockquote>

      *

      * @param key the key for the desired string array

      * @exception NullPointerException if <code>key</code> is <code>null</code>

      * @exception MissingResourceException if no object for the given key can be found

      * @exception ClassCastException if the object found for the given key is not a string array

      * @return the string array for the given key

      */

     public final String[] getStringArray(String key) {

         return (String[]) getObject(key);

     }

     /**

      * Gets an object for the given key from this resource bundle or one of its parents.

      * This method first tries to obtain the object from this resource bundle using

      * {@link #handleGetObject(java.lang.String) handleGetObject}.

      * If not successful, and the parent resource bundle is not null,

      * it calls the parent's <code>getObject</code> method.

      * If still not successful, it throws a MissingResourceException.

      *

      * @param key the key for the desired object

      * @exception NullPointerException if <code>key</code> is <code>null</code>

      * @exception MissingResourceException if no object for the given key can be found

      * @return the object for the given key

      */

     public final Object getObject(String key) {

         Object obj = handleGetObject(key);

         if (obj == null) {

             if (parent != null) {

                 obj = parent.getObject(key);

             }

             if (obj == null)

                 throw new MissingResourceException("Can't find resource for bundle "

                                                    +this.getClass().getName()

                                                    +", key "+key,

                                                    this.getClass().getName(),

                                                    key);

         }

         return obj;

     }

     /**

      * Returns the locale of this resource bundle. This method can be used after a

      * call to getBundle() to determine whether the resource bundle returned really

      * corresponds to the requested locale or is a fallback.

      *

      * @return the locale of this resource bundle

      */

     public Locale getLocale() {

         return locale;

     }

     /*

      * Automatic determination of the ClassLoader to be used to load

      * resources on behalf of the client.  N.B. The client is getLoader's

      * caller's caller.

      */

     private static ClassLoader getLoader() {

         Class[] stack = getClassContext();

         /* Magic number 2 identifies our caller's caller */

         Class c = stack[2];

         ClassLoader cl = (c == null) ? null : c.getClassLoader();

         if (cl == null) {

             // When the caller's loader is the boot class loader, cl is null

             // here. In that case, ClassLoader.getSystemClassLoader() may

             // return the same class loader that the application is

             // using. We therefore use a wrapper ClassLoader to create a

             // separate scope for bundles loaded on behalf of the Java

             // runtime so that these bundles cannot be returned from the

             // cache to the application (5048280).

             cl = RBClassLoader.INSTANCE;

         }

         return cl;

     }

     private static native Class[] getClassContext();

     /**

      * A wrapper of ClassLoader.getSystemClassLoader().

      */

     private static class RBClassLoader extends ClassLoader {

         private static final RBClassLoader INSTANCE = AccessController.doPrivileged(

                     new PrivilegedAction<RBClassLoader>() {

                         public RBClassLoader run() {

                             return new RBClassLoader();

                         }

                     });

         private static final ClassLoader loader = ClassLoader.getSystemClassLoader();

         private RBClassLoader() {

         }

         public Class<?> loadClass(String name) throws ClassNotFoundException {

             if (loader != null) {

                 return loader.loadClass(name);

             }

             return Class.forName(name);

         }

         public URL getResource(String name) {

             if (loader != null) {

                 return loader.getResource(name);

             }

             return ClassLoader.getSystemResource(name);

         }

         public InputStream getResourceAsStream(String name) {

             if (loader != null) {

                 return loader.getResourceAsStream(name);

             }

             return ClassLoader.getSystemResourceAsStream(name);

         }

     }

     /**

      * Sets the parent bundle of this bundle.

      * The parent bundle is searched by {@link #getObject getObject}

      * when this bundle does not contain a particular resource.

      *

      * @param parent this bundle's parent bundle.

      */

     protected void setParent(ResourceBundle parent) {

         assert parent != NONEXISTENT_BUNDLE;

         this.parent = parent;

     }

     /**

      * Key used for cached resource bundles.  The key checks the base

      * name, the locale, and the class loader to determine if the

      * resource is a match to the requested one. The loader may be

      * null, but the base name and the locale must have a non-null

      * value.

      */

     private static final class CacheKey implements Cloneable {

         // These three are the actual keys for lookup in Map.

         private String name;

         private Locale locale;

         private LoaderReference loaderRef;

         // bundle format which is necessary for calling

         // Control.needsReload().

         private String format;

         // These time values are in CacheKey so that NONEXISTENT_BUNDLE

         // doesn't need to be cloned for caching.

         // The time when the bundle has been loaded

         private volatile long loadTime;

         // The time when the bundle expires in the cache, or either

         // Control.TTL_DONT_CACHE or Control.TTL_NO_EXPIRATION_CONTROL.

         private volatile long expirationTime;

         // Placeholder for an error report by a Throwable

         private Throwable cause;

         // Hash code value cache to avoid recalculating the hash code

         // of this instance.

         private int hashCodeCache;

         CacheKey(String baseName, Locale locale, ClassLoader loader) {

             this.name = baseName;

             this.locale = locale;

             if (loader == null) {

                 this.loaderRef = null;

             } else {

                 loaderRef = new LoaderReference(loader, referenceQueue, this);

             }

             calculateHashCode();

         }

         String getName() {

             return name;

         }

         CacheKey setName(String baseName) {

             if (!this.name.equals(baseName)) {

                 this.name = baseName;

                 calculateHashCode();

             }

             return this;

         }

         Locale getLocale() {

             return locale;

         }

         CacheKey setLocale(Locale locale) {

             if (!this.locale.equals(locale)) {

                 this.locale = locale;

                 calculateHashCode();

             }

             return this;

         }

         ClassLoader getLoader() {

             return (loaderRef != null) ? loaderRef.get() : null;

         }

         public boolean equals(Object other) {

             if (this == other) {

                 return true;

             }

             try {

                 final CacheKey otherEntry = (CacheKey)other;

                 //quick check to see if they are not equal

                 if (hashCodeCache != otherEntry.hashCodeCache) {

                     return false;

                 }

                 //are the names the same?

                 if (!name.equals(otherEntry.name)) {

                     return false;

                 }

                 // are the locales the same?

                 if (!locale.equals(otherEntry.locale)) {

                     return false;

                 }

                 //are refs (both non-null) or (both null)?

                 if (loaderRef == null) {

                     return otherEntry.loaderRef == null;

                 }

                 ClassLoader loader = loaderRef.get();

                 return (otherEntry.loaderRef != null)

                         // with a null reference we can no longer find

                         // out which class loader was referenced; so

                         // treat it as unequal

                         && (loader != null)

                         && (loader == otherEntry.loaderRef.get());

             } catch (NullPointerException e) {

             } catch (ClassCastException e) {

             }

             return false;

         }

         public int hashCode() {

             return hashCodeCache;

         }

         private void calculateHashCode() {

             hashCodeCache = name.hashCode() << 3;

             hashCodeCache ^= locale.hashCode();

             ClassLoader loader = getLoader();

             if (loader != null) {

                 hashCodeCache ^= loader.hashCode();

             }

         }

         public Object clone() {

             try {

                 CacheKey clone = (CacheKey) super.clone();

                 if (loaderRef != null) {

                     clone.loaderRef = new LoaderReference(loaderRef.get(),

                                                           referenceQueue, clone);

                 }

                 // Clear the reference to a Throwable

                 clone.cause = null;

                 return clone;

             } catch (CloneNotSupportedException e) {

                 //this should never happen

                 throw new InternalError();

             }

         }

         String getFormat() {

             return format;

         }

         void setFormat(String format) {

             this.format = format;

         }

         private void setCause(Throwable cause) {

             if (this.cause == null) {

                 this.cause = cause;

             } else {

                 // Override the cause if the previous one is

                 // ClassNotFoundException.

                 if (this.cause instanceof ClassNotFoundException) {

                     this.cause = cause;

                 }

             }

         }

         private Throwable getCause() {

             return cause;

         }

         public String toString() {

             String l = locale.toString();

             if (l.length() == 0) {

                 if (locale.getVariant().length() != 0) {

                     l = "__" + locale.getVariant();

                 } else {

                     l = "\"\"";

                 }

             }

             return "CacheKey[" + name + ", lc=" + l + ", ldr=" + getLoader()

                 + "(format=" + format + ")]";

         }

     }

     /**

      * The common interface to get a CacheKey in LoaderReference and

      * BundleReference.

      */

     private static interface CacheKeyReference {

         public CacheKey getCacheKey();

     }

     /**

      * References to class loaders are weak references, so that they can be

      * garbage collected when nobody else is using them. The ResourceBundle

      * class has no reason to keep class loaders alive.

      */

     private static final class LoaderReference extends WeakReference<ClassLoader>

                                                implements CacheKeyReference {

         private CacheKey cacheKey;

         LoaderReference(ClassLoader referent, ReferenceQueue q, CacheKey key) {

             super(referent, q);

             cacheKey = key;

         }

         public CacheKey getCacheKey() {

             return cacheKey;

         }

     }

     /**

      * References to bundles are soft references so that they can be garbage

      * collected when they have no hard references.

      */

     private static final class BundleReference extends SoftReference<ResourceBundle>

                                                implements CacheKeyReference {

         private CacheKey cacheKey;

         BundleReference(ResourceBundle referent, ReferenceQueue q, CacheKey key) {

             super(referent, q);

             cacheKey = key;

         }

         public CacheKey getCacheKey() {

             return cacheKey;

         }

     }

     /**

      * Gets a resource bundle using the specified base name, the default locale,

      * and the caller's class loader. Calling this method is equivalent to calling

      * <blockquote>

      * <code>getBundle(baseName, Locale.getDefault(), this.getClass().getClassLoader())</code>,

      * </blockquote>

      * except that <code>getClassLoader()</code> is run with the security

      * privileges of <code>ResourceBundle</code>.

      * See {@link #getBundle(String, Locale, ClassLoader) getBundle}

      * for a complete description of the search and instantiation strategy.

      *

      * @param baseName the base name of the resource bundle, a fully qualified class name

      * @exception java.lang.NullPointerException

      *     if <code>baseName</code> is <code>null</code>

      * @exception MissingResourceException

      *     if no resource bundle for the specified base name can be found

      * @return a resource bundle for the given base name and the default locale

      */

     public static final ResourceBundle getBundle(String baseName)

     {

         return getBundleImpl(baseName, Locale.getDefault(),

                              /* must determine loader here, else we break stack invariant */

                              getLoader(),

                              Control.INSTANCE);

     }

     /**

      * Returns a resource bundle using the specified base name, the

      * default locale and the specified control. Calling this method

      * is equivalent to calling

      * <pre>

      * getBundle(baseName, Locale.getDefault(),

      *           this.getClass().getClassLoader(), control),

      * </pre>

      * except that <code>getClassLoader()</code> is run with the security

      * privileges of <code>ResourceBundle</code>.  See {@link

      * #getBundle(String, Locale, ClassLoader, Control) getBundle} for the

      * complete description of the resource bundle loading process with a

      * <code>ResourceBundle.Control</code>.

      *

      * @param baseName

      *        the base name of the resource bundle, a fully qualified class

      *        name

      * @param control

      *        the control which gives information for the resource bundle

      *        loading process

      * @return a resource bundle for the given base name and the default

      *        locale

      * @exception NullPointerException

      *        if <code>baseName</code> or <code>control</code> is

      *        <code>null</code>

      * @exception MissingResourceException

      *        if no resource bundle for the specified base name can be found

      * @exception IllegalArgumentException

      *        if the given <code>control</code> doesn't perform properly

      *        (e.g., <code>control.getCandidateLocales</code> returns null.)

      *        Note that validation of <code>control</code> is performed as

      *        needed.

      * @since 1.6

      */

     public static final ResourceBundle getBundle(String baseName,

                                                  Control control) {

         return getBundleImpl(baseName, Locale.getDefault(),

                              /* must determine loader here, else we break stack invariant */

                              getLoader(),

                              control);

     }

     /**

      * Gets a resource bundle using the specified base name and locale,

      * and the caller's class loader. Calling this method is equivalent to calling

      * <blockquote>

      * <code>getBundle(baseName, locale, this.getClass().getClassLoader())</code>,

      * </blockquote>

      * except that <code>getClassLoader()</code> is run with the security

      * privileges of <code>ResourceBundle</code>.

      * See {@link #getBundle(String, Locale, ClassLoader) getBundle}

      * for a complete description of the search and instantiation strategy.

      *

      * @param baseName

      *        the base name of the resource bundle, a fully qualified class name

      * @param locale

      *        the locale for which a resource bundle is desired

      * @exception NullPointerException

      *        if <code>baseName</code> or <code>locale</code> is <code>null</code>

      * @exception MissingResourceException

      *        if no resource bundle for the specified base name can be found

      * @return a resource bundle for the given base name and locale

      */

     public static final ResourceBundle getBundle(String baseName,

                                                  Locale locale)

     {

         return getBundleImpl(baseName, locale,

                              /* must determine loader here, else we break stack invariant */

                              getLoader(),

                              Control.INSTANCE);

     }

     /**

      * Returns a resource bundle using the specified base name, target

      * locale and control, and the caller's class loader. Calling this

      * method is equivalent to calling

      * <pre>

      * getBundle(baseName, targetLocale, this.getClass().getClassLoader(),

      *           control),

      * </pre>

      * except that <code>getClassLoader()</code> is run with the security

      * privileges of <code>ResourceBundle</code>.  See {@link

      * #getBundle(String, Locale, ClassLoader, Control) getBundle} for the

      * complete description of the resource bundle loading process with a

      * <code>ResourceBundle.Control</code>.

      *

      * @param baseName

      *        the base name of the resource bundle, a fully qualified

      *        class name

      * @param targetLocale

      *        the locale for which a resource bundle is desired

      * @param control

      *        the control which gives information for the resource

      *        bundle loading process

      * @return a resource bundle for the given base name and a

      *        <code>Locale</code> in <code>locales</code>

      * @exception NullPointerException

      *        if <code>baseName</code>, <code>locales</code> or

      *        <code>control</code> is <code>null</code>

      * @exception MissingResourceException

      *        if no resource bundle for the specified base name in any

      *        of the <code>locales</code> can be found.

      * @exception IllegalArgumentException

      *        if the given <code>control</code> doesn't perform properly

      *        (e.g., <code>control.getCandidateLocales</code> returns null.)

      *        Note that validation of <code>control</code> is performed as

      *        needed.

      * @since 1.6

      */

     public static final ResourceBundle getBundle(String baseName, Locale targetLocale,

                                                  Control control) {

         return getBundleImpl(baseName, targetLocale,

                              /* must determine loader here, else we break stack invariant */

                              getLoader(),

                              control);

     }

     /**

      * Gets a resource bundle using the specified base name, locale, and class

      * loader.

      *

      * <p><a name="default_behavior"/>This method behaves the same as calling

      * {@link #getBundle(String, Locale, ClassLoader, Control)} passing a

      * default instance of {@link Control}. The following describes this behavior.

      *

      * <p><code>getBundle</code> uses the base name, the specified locale, and

      * the default locale (obtained from {@link java.util.Locale#getDefault()

      * Locale.getDefault}) to generate a sequence of <a

      * name="candidates"><em>candidate bundle names</em></a>.  If the specified

      * locale's language, script, country, and variant are all empty strings,

      * then the base name is the only candidate bundle name.  Otherwise, a list

      * of candidate locales is generated from the attribute values of the

      * specified locale (language, script, country and variant) and appended to

      * the base name.  Typically, this will look like the following:

      *

      * <pre>

      *     baseName + "_" + language + "_" + script + "_" + country + "_" + variant

      *     baseName + "_" + language + "_" + script + "_" + country

      *     baseName + "_" + language + "_" + script

      *     baseName + "_" + language + "_" + country + "_" + variant

      *     baseName + "_" + language + "_" + country

      *     baseName + "_" + language

      * </pre>

      *

      * <p>Candidate bundle names where the final component is an empty string

      * are omitted, along with the underscore.  For example, if country is an

      * empty string, the second and the fifth candidate bundle names above

      * would be omitted.  Also, if script is an empty string, the candidate names

      * including script are omitted.  For example, a locale with language "de"

      * and variant "JAVA" will produce candidate names with base name

      * "MyResource" below.

      *

      * <pre>

      *     MyResource_de__JAVA

      *     MyResource_de

      * </pre>

      *

      * In the case that the variant contains one or more underscores ('_'), a

      * sequence of bundle names generated by truncating the last underscore and

      * the part following it is inserted after a candidate bundle name with the

      * original variant.  For example, for a locale with language "en", script

      * "Latn, country "US" and variant "WINDOWS_VISTA", and bundle base name

      * "MyResource", the list of candidate bundle names below is generated:

      *

      * <pre>

      * MyResource_en_Latn_US_WINDOWS_VISTA

      * MyResource_en_Latn_US_WINDOWS

      * MyResource_en_Latn_US

      * MyResource_en_Latn

      * MyResource_en_US_WINDOWS_VISTA

      * MyResource_en_US_WINDOWS

      * MyResource_en_US

      * MyResource_en

      * </pre>

      *

      * <blockquote><b>Note:</b> For some <code>Locale</code>s, the list of

      * candidate bundle names contains extra names, or the order of bundle names

      * is slightly modified.  See the description of the default implementation

      * of {@link Control#getCandidateLocales(String, Locale)

      * getCandidateLocales} for details.</blockquote>

      *

      * <p><code>getBundle</code> then iterates over the candidate bundle names

      * to find the first one for which it can <em>instantiate</em> an actual

      * resource bundle. It uses the default controls' {@link Control#getFormats

      * getFormats} method, which generates two bundle names for each generated

      * name, the first a class name and the second a properties file name. For

      * each candidate bundle name, it attempts to create a resource bundle:

      *

      * <ul><li>First, it attempts to load a class using the generated class name.

      * If such a class can be found and loaded using the specified class

      * loader, is assignment compatible with ResourceBundle, is accessible from

      * ResourceBundle, and can be instantiated, <code>getBundle</code> creates a

      * new instance of this class and uses it as the <em>result resource

      * bundle</em>.

      *

      * <li>Otherwise, <code>getBundle</code> attempts to locate a property

      * resource file using the generated properties file name.  It generates a

      * path name from the candidate bundle name by replacing all "." characters

      * with "/" and appending the string ".properties".  It attempts to find a

      * "resource" with this name using {@link

      * java.lang.ClassLoader#getResource(java.lang.String)

      * ClassLoader.getResource}.  (Note that a "resource" in the sense of

      * <code>getResource</code> has nothing to do with the contents of a

      * resource bundle, it is just a container of data, such as a file.)  If it

      * finds a "resource", it attempts to create a new {@link

      * PropertyResourceBundle} instance from its contents.  If successful, this

      * instance becomes the <em>result resource bundle</em>.  </ul>

      *

      * <p>This continues until a result resource bundle is instantiated or the

      * list of candidate bundle names is exhausted.  If no matching resource

      * bundle is found, the default control's {@link Control#getFallbackLocale

      * getFallbackLocale} method is called, which returns the current default

      * locale.  A new sequence of candidate locale names is generated using this

      * locale and and searched again, as above.

      *

      * <p>If still no result bundle is found, the base name alone is looked up. If

      * this still fails, a <code>MissingResourceException</code> is thrown.

      *

      * <p><a name="parent_chain"/> Once a result resource bundle has been found,

      * its <em>parent chain</em> is instantiated.  If the result bundle already

      * has a parent (perhaps because it was returned from a cache) the chain is

      * complete.

      *

      * <p>Otherwise, <code>getBundle</code> examines the remainder of the

      * candidate locale list that was used during the pass that generated the

      * result resource bundle.  (As before, candidate bundle names where the

      * final component is an empty string are omitted.)  When it comes to the

      * end of the candidate list, it tries the plain bundle name.  With each of the

      * candidate bundle names it attempts to instantiate a resource bundle (first

      * looking for a class and then a properties file, as described above).

      *

      * <p>Whenever it succeeds, it calls the previously instantiated resource

      * bundle's {@link #setParent(java.util.ResourceBundle) setParent} method

      * with the new resource bundle.  This continues until the list of names

      * is exhausted or the current bundle already has a non-null parent.

      *

      * <p>Once the parent chain is complete, the bundle is returned.

      *

      * <p><b>Note:</b> <code>getBundle</code> caches instantiated resource

      * bundles and might return the same resource bundle instance multiple times.

      *

      * <p><b>Note:</b>The <code>baseName</code> argument should be a fully

      * qualified class name. However, for compatibility with earlier versions,

      * Sun's Java SE Runtime Environments do not verify this, and so it is

      * possible to access <code>PropertyResourceBundle</code>s by specifying a

      * path name (using "/") instead of a fully qualified class name (using

      * ".").

      *

      * <p><a name="default_behavior_example"/>

      * <strong>Example:</strong>

      * <p>

      * The following class and property files are provided:

      * <pre>

      *     MyResources.class

      *     MyResources.properties

      *     MyResources_fr.properties

      *     MyResources_fr_CH.class

      *     MyResources_fr_CH.properties

      *     MyResources_en.properties

      *     MyResources_es_ES.class

      * </pre>

      *

      * The contents of all files are valid (that is, public non-abstract

      * subclasses of <code>ResourceBundle</code> for the ".class" files,

      * syntactically correct ".properties" files).  The default locale is

      * <code>Locale("en", "GB")</code>.

      *

      * <p>Calling <code>getBundle</code> with the locale arguments below will

      * instantiate resource bundles as follows:

      *

      * <table>

      * <tr><td>Locale("fr", "CH")</td><td>MyResources_fr_CH.class, parent MyResources_fr.properties, parent MyResources.class</td></tr>

      * <tr><td>Locale("fr", "FR")</td><td>MyResources_fr.properties, parent MyResources.class</td></tr>

      * <tr><td>Locale("de", "DE")</td><td>MyResources_en.properties, parent MyResources.class</td></tr>

      * <tr><td>Locale("en", "US")</td><td>MyResources_en.properties, parent MyResources.class</td></tr>

      * <tr><td>Locale("es", "ES")</td><td>MyResources_es_ES.class, parent MyResources.class</td></tr>

      * </table>

      *

      * <p>The file MyResources_fr_CH.properties is never used because it is

      * hidden by the MyResources_fr_CH.class. Likewise, MyResources.properties

      * is also hidden by MyResources.class.

      *

      * @param baseName the base name of the resource bundle, a fully qualified class name

      * @param locale the locale for which a resource bundle is desired

      * @param loader the class loader from which to load the resource bundle

      * @return a resource bundle for the given base name and locale

      * @exception java.lang.NullPointerException

      *        if <code>baseName</code>, <code>locale</code>, or <code>loader</code> is <code>null</code>

      * @exception MissingResourceException

      *        if no resource bundle for the specified base name can be found

      * @since 1.2

      */

     public static ResourceBundle getBundle(String baseName, Locale locale,

                                            ClassLoader loader)

     {

         if (loader == null) {

             throw new NullPointerException();

         }

         return getBundleImpl(baseName, locale, loader, Control.INSTANCE);

     }

     /**

      * Returns a resource bundle using the specified base name, target

      * locale, class loader and control. Unlike the {@linkplain

      * #getBundle(String, Locale, ClassLoader) <code>getBundle</code>

      * factory methods with no <code>control</code> argument}, the given

      * <code>control</code> specifies how to locate and instantiate resource

      * bundles. Conceptually, the bundle loading process with the given

      * <code>control</code> is performed in the following steps.

      *

      * <p>

      * <ol>

      * <li>This factory method looks up the resource bundle in the cache for

      * the specified <code>baseName</code>, <code>targetLocale</code> and

      * <code>loader</code>.  If the requested resource bundle instance is

      * found in the cache and the time-to-live periods of the instance and

      * all of its parent instances have not expired, the instance is returned

      * to the caller. Otherwise, this factory method proceeds with the

      * loading process below.</li>

      *

      * <li>The {@link ResourceBundle.Control#getFormats(String)

      * control.getFormats} method is called to get resource bundle formats

      * to produce bundle or resource names. The strings

      * <code>"java.class"</code> and <code>"java.properties"</code>

      * designate class-based and {@linkplain PropertyResourceBundle

      * property}-based resource bundles, respectively. Other strings

      * starting with <code>"java."</code> are reserved for future extensions

      * and must not be used for application-defined formats. Other strings

      * designate application-defined formats.</li>

      *

      * <li>The {@link ResourceBundle.Control#getCandidateLocales(String,

      * Locale) control.getCandidateLocales} method is called with the target

      * locale to get a list of <em>candidate <code>Locale</code>s</em> for

      * which resource bundles are searched.</li>

      *

      * <li>The {@link ResourceBundle.Control#newBundle(String, Locale,

      * String, ClassLoader, boolean) control.newBundle} method is called to

      * instantiate a <code>ResourceBundle</code> for the base bundle name, a

      * candidate locale, and a format. (Refer to the note on the cache

      * lookup below.) This step is iterated over all combinations of the

      * candidate locales and formats until the <code>newBundle</code> method

      * returns a <code>ResourceBundle</code> instance or the iteration has

      * used up all the combinations. For example, if the candidate locales

      * are <code>Locale("de", "DE")</code>, <code>Locale("de")</code> and

      * <code>Locale("")</code> and the formats are <code>"java.class"</code>

      * and <code>"java.properties"</code>, then the following is the

      * sequence of locale-format combinations to be used to call

      * <code>control.newBundle</code>.

      *

      * <table style="width: 50%; text-align: left; margin-left: 40px;"

      *  border="0" cellpadding="2" cellspacing="2">

      * <tbody><code>

      * <tr>

      * <td

      * style="vertical-align: top; text-align: left; font-weight: bold; width: 50%;">Locale<br>

      * </td>

      * <td

      * style="vertical-align: top; text-align: left; font-weight: bold; width: 50%;">format<br>

      * </td>

      * </tr>

      * <tr>

      * <td style="vertical-align: top; width: 50%;">Locale("de", "DE")<br>

      * </td>

      * <td style="vertical-align: top; width: 50%;">java.class<br>

      * </td>

      * </tr>

      * <tr>

      * <td style="vertical-align: top; width: 50%;">Locale("de", "DE")</td>

      * <td style="vertical-align: top; width: 50%;">java.properties<br>

      * </td>

      * </tr>

      * <tr>

      * <td style="vertical-align: top; width: 50%;">Locale("de")</td>

      * <td style="vertical-align: top; width: 50%;">java.class</td>

      * </tr>

      * <tr>

      * <td style="vertical-align: top; width: 50%;">Locale("de")</td>

      * <td style="vertical-align: top; width: 50%;">java.properties</td>

      * </tr>

      * <tr>

      * <td style="vertical-align: top; width: 50%;">Locale("")<br>

      * </td>

      * <td style="vertical-align: top; width: 50%;">java.class</td>

      * </tr>

      * <tr>

      * <td style="vertical-align: top; width: 50%;">Locale("")</td>

      * <td style="vertical-align: top; width: 50%;">java.properties</td>

      * </tr>

      * </code></tbody>

      * </table>

      * </li>

      *

      * <li>If the previous step has found no resource bundle, proceed to

      * Step 6. If a bundle has been found that is a base bundle (a bundle

      * for <code>Locale("")</code>), and the candidate locale list only contained

      * <code>Locale("")</code>, return the bundle to the caller. If a bundle

      * has been found that is a base bundle, but the candidate locale list

      * contained locales other than Locale(""), put the bundle on hold and

      * proceed to Step 6. If a bundle has been found that is not a base

      * bundle, proceed to Step 7.</li>

      *

      * <li>The {@link ResourceBundle.Control#getFallbackLocale(String,

      * Locale) control.getFallbackLocale} method is called to get a fallback

      * locale (alternative to the current target locale) to try further

      * finding a resource bundle. If the method returns a non-null locale,

      * it becomes the next target locale and the loading process starts over

      * from Step 3. Otherwise, if a base bundle was found and put on hold in

      * a previous Step 5, it is returned to the caller now. Otherwise, a

      * MissingResourceException is thrown.</li>

      *

      * <li>At this point, we have found a resource bundle that's not the

      * base bundle. If this bundle set its parent during its instantiation,

      * it is returned to the caller. Otherwise, its <a

      * href="./ResourceBundle.html#parent_chain">parent chain</a> is

      * instantiated based on the list of candidate locales from which it was

      * found. Finally, the bundle is returned to the caller.</li>

      * </ol>

      *

      * <p>During the resource bundle loading process above, this factory

      * method looks up the cache before calling the {@link

      * Control#newBundle(String, Locale, String, ClassLoader, boolean)

      * control.newBundle} method.  If the time-to-live period of the

      * resource bundle found in the cache has expired, the factory method

      * calls the {@link ResourceBundle.Control#needsReload(String, Locale,

      * String, ClassLoader, ResourceBundle, long) control.needsReload}

      * method to determine whether the resource bundle needs to be reloaded.

      * If reloading is required, the factory method calls

      * <code>control.newBundle</code> to reload the resource bundle.  If

      * <code>control.newBundle</code> returns <code>null</code>, the factory

      * method puts a dummy resource bundle in the cache as a mark of

      * nonexistent resource bundles in order to avoid lookup overhead for

      * subsequent requests. Such dummy resource bundles are under the same

      * expiration control as specified by <code>control</code>.

      *

      * <p>All resource bundles loaded are cached by default. Refer to

      * {@link Control#getTimeToLive(String,Locale)

      * control.getTimeToLive} for details.

      *

      * <p>The following is an example of the bundle loading process with the

      * default <code>ResourceBundle.Control</code> implementation.

      *

      * <p>Conditions:

      * <ul>

      * <li>Base bundle name: <code>foo.bar.Messages</code>

      * <li>Requested <code>Locale</code>: {@link Locale#ITALY}</li>

      * <li>Default <code>Locale</code>: {@link Locale#FRENCH}</li>

      * <li>Available resource bundles:

      * <code>foo/bar/Messages_fr.properties</code> and

      * <code>foo/bar/Messages.properties</code></li>

      * </ul>

      *

      * <p>First, <code>getBundle</code> tries loading a resource bundle in

      * the following sequence.

      *

      * <ul>

      * <li>class <code>foo.bar.Messages_it_IT</code>

      * <li>file <code>foo/bar/Messages_it_IT.properties</code>

      * <li>class <code>foo.bar.Messages_it</code></li>

      * <li>file <code>foo/bar/Messages_it.properties</code></li>

      * <li>class <code>foo.bar.Messages</code></li>

      * <li>file <code>foo/bar/Messages.properties</code></li>

      * </ul>

      *

      * <p>At this point, <code>getBundle</code> finds

      * <code>foo/bar/Messages.properties</code>, which is put on hold

      * because it's the base bundle.  <code>getBundle</code> calls {@link

      * Control#getFallbackLocale(String, Locale)

      * control.getFallbackLocale("foo.bar.Messages", Locale.ITALY)} which

      * returns <code>Locale.FRENCH</code>. Next, <code>getBundle</code>

      * tries loading a bundle in the following sequence.

      *

      * <ul>

      * <li>class <code>foo.bar.Messages_fr</code></li>

      * <li>file <code>foo/bar/Messages_fr.properties</code></li>

      * <li>class <code>foo.bar.Messages</code></li>

      * <li>file <code>foo/bar/Messages.properties</code></li>

      * </ul>

      *

      * <p><code>getBundle</code> finds

      * <code>foo/bar/Messages_fr.properties</code> and creates a

      * <code>ResourceBundle</code> instance. Then, <code>getBundle</code>

      * sets up its parent chain from the list of the candiate locales.  Only

      * <code>foo/bar/Messages.properties</code> is found in the list and

      * <code>getBundle</code> creates a <code>ResourceBundle</code> instance

      * that becomes the parent of the instance for

      * <code>foo/bar/Messages_fr.properties</code>.

      *

      * @param baseName

      *        the base name of the resource bundle, a fully qualified

      *        class name

      * @param targetLocale

      *        the locale for which a resource bundle is desired

      * @param loader

      *        the class loader from which to load the resource bundle

      * @param control

      *        the control which gives information for the resource

      *        bundle loading process

      * @return a resource bundle for the given base name and locale

      * @exception NullPointerException

      *        if <code>baseName</code>, <code>targetLocale</code>,

      *        <code>loader</code>, or <code>control</code> is

      *        <code>null</code>

      * @exception MissingResourceException

      *        if no resource bundle for the specified base name can be found

      * @exception IllegalArgumentException

      *        if the given <code>control</code> doesn't perform properly

      *        (e.g., <code>control.getCandidateLocales</code> returns null.)

      *        Note that validation of <code>control</code> is performed as

      *        needed.

      * @since 1.6

      */

     public static ResourceBundle getBundle(String baseName, Locale targetLocale,

                                            ClassLoader loader, Control control) {

         if (loader == null || control == null) {

             throw new NullPointerException();

         }

         return getBundleImpl(baseName, targetLocale, loader, control);

     }

     private static ResourceBundle getBundleImpl(String baseName, Locale locale,

                                                 ClassLoader loader, Control control) {

         if (locale == null || control == null) {

             throw new NullPointerException();

         }

         // We create a CacheKey here for use by this call. The base

         // name and loader will never change during the bundle loading

         // process. We have to make sure that the locale is set before

         // using it as a cache key.

         CacheKey cacheKey = new CacheKey(baseName, locale, loader);

         ResourceBundle bundle = null;

         // Quick lookup of the cache.

         BundleReference bundleRef = cacheList.get(cacheKey);

         if (bundleRef != null) {

             bundle = bundleRef.get();

             bundleRef = null;

         }

         // If this bundle and all of its parents are valid (not expired),

         // then return this bundle. If any of the bundles is expired, we

         // don't call control.needsReload here but instead drop into the

         // complete loading process below.

         if (isValidBundle(bundle) && hasValidParentChain(bundle)) {

             return bundle;

         }

         // No valid bundle was found in the cache, so we need to load the

         // resource bundle and its parents.

         boolean isKnownControl = (control == Control.INSTANCE) ||

                                    (control instanceof SingleFormatControl);

         List<String> formats = control.getFormats(baseName);

         if (!isKnownControl && !checkList(formats)) {

             throw new IllegalArgumentException("Invalid Control: getFormats");

         }

         ResourceBundle baseBundle = null;

         for (Locale targetLocale = locale;

              targetLocale != null;

              targetLocale = control.getFallbackLocale(baseName, targetLocale)) {

             List<Locale> candidateLocales = control.getCandidateLocales(baseName, targetLocale);

             if (!isKnownControl && !checkList(candidateLocales)) {

                 throw new IllegalArgumentException("Invalid Control: getCandidateLocales");

             }

             bundle = findBundle(cacheKey, candidateLocales, formats, 0, control, baseBundle);

             // If the loaded bundle is the base bundle and exactly for the

             // requested locale or the only candidate locale, then take the

             // bundle as the resulting one. If the loaded bundle is the base

             // bundle, it's put on hold until we finish processing all

             // fallback locales.

             if (isValidBundle(bundle)) {

                 boolean isBaseBundle = Locale.ROOT.equals(bundle.locale);

                 if (!isBaseBundle || bundle.locale.equals(locale)

                     || (candidateLocales.size() == 1

                         && bundle.locale.equals(candidateLocales.get(0)))) {

                     break;

                 }

                 // If the base bundle has been loaded, keep the reference in

                 // baseBundle so that we can avoid any redundant loading in case

                 // the control specify not to cache bundles.

                 if (isBaseBundle && baseBundle == null) {

                     baseBundle = bundle;

                 }

             }

         }

         if (bundle == null) {

             if (baseBundle == null) {

                 throwMissingResourceException(baseName, locale, cacheKey.getCause());

             }

             bundle = baseBundle;

         }

         return bundle;

     }

     /**

      * Checks if the given <code>List</code> is not null, not empty,

      * not having null in its elements.

      */

     private static final boolean checkList(List a) {

         boolean valid = (a != null && a.size() != 0);

         if (valid) {

             int size = a.size();

             for (int i = 0; valid && i < size; i++) {

                 valid = (a.get(i) != null);

             }

         }

         return valid;

     }

     private static final ResourceBundle findBundle(CacheKey cacheKey,

                                                    List<Locale> candidateLocales,

                                                    List<String> formats,

                                                    int index,

                                                    Control control,

                                                    ResourceBundle baseBundle) {

         Locale targetLocale = candidateLocales.get(index);

         ResourceBundle parent = null;

         if (index != candidateLocales.size() - 1) {

             parent = findBundle(cacheKey, candidateLocales, formats, index + 1,

                                 control, baseBundle);

         } else if (baseBundle != null && Locale.ROOT.equals(targetLocale)) {

             return baseBundle;

         }

         // Before we do the real loading work, see whether we need to

         // do some housekeeping: If references to class loaders or

         // resource bundles have been nulled out, remove all related

         // information from the cache.

         Object ref;

         while ((ref = referenceQueue.poll()) != null) {

             cacheList.remove(((CacheKeyReference)ref).getCacheKey());

         }

         // flag indicating the resource bundle has expired in the cache

         boolean expiredBundle = false;

         // First, look up the cache to see if it's in the cache, without

         // attempting to load bundle.

         cacheKey.setLocale(targetLocale);

         ResourceBundle bundle = findBundleInCache(cacheKey, control);

         if (isValidBundle(bundle)) {

             expiredBundle = bundle.expired;

             if (!expiredBundle) {

                 // If its parent is the one asked for by the candidate

                 // locales (the runtime lookup path), we can take the cached

                 // one. (If it's not identical, then we'd have to check the

                 // parent's parents to be consistent with what's been

                 // requested.)

                 if (bundle.parent == parent) {

                     return bundle;

                 }

                 // Otherwise, remove the cached one since we can't keep

                 // the same bundles having different parents.

                 BundleReference bundleRef = cacheList.get(cacheKey);

                 if (bundleRef != null && bundleRef.get() == bundle) {

                     cacheList.remove(cacheKey, bundleRef);

                 }

             }

         }

         if (bundle != NONEXISTENT_BUNDLE) {

             CacheKey constKey = (CacheKey) cacheKey.clone();

             try {

                 bundle = loadBundle(cacheKey, formats, control, expiredBundle);

                 if (bundle != null) {

                     if (bundle.parent == null) {

                         bundle.setParent(parent);

                     }

                     bundle.locale = targetLocale;

                     bundle = putBundleInCache(cacheKey, bundle, control);

                     return bundle;

                 }

                 // Put NONEXISTENT_BUNDLE in the cache as a mark that there's no bundle

                 // instance for the locale.

                 putBundleInCache(cacheKey, NONEXISTENT_BUNDLE, control);

             } finally {

                 if (constKey.getCause() instanceof InterruptedException) {

                     Thread.currentThread().interrupt();

                 }

             }

         }

         return parent;

     }

     private static final ResourceBundle loadBundle(CacheKey cacheKey,

                                                    List<String> formats,

                                                    Control control,

                                                    boolean reload) {

         // Here we actually load the bundle in the order of formats

         // specified by the getFormats() value.

         Locale targetLocale = cacheKey.getLocale();

         ResourceBundle bundle = null;

         int size = formats.size();

         for (int i = 0; i < size; i++) {

             String format = formats.get(i);

             try {

                 bundle = control.newBundle(cacheKey.getName(), targetLocale, format,

                                            cacheKey.getLoader(), reload);

             } catch (LinkageError error) {

                 // We need to handle the LinkageError case due to

                 // inconsistent case-sensitivity in ClassLoader.

                 // See 6572242 for details.

                 cacheKey.setCause(error);

             } catch (Exception cause) {

                 cacheKey.setCause(cause);

             }

             if (bundle != null) {

                 // Set the format in the cache key so that it can be

                 // used when calling needsReload later.

                 cacheKey.setFormat(format);

                 bundle.name = cacheKey.getName();

                 bundle.locale = targetLocale;

                 // Bundle provider might reuse instances. So we should make

                 // sure to clear the expired flag here.

                 bundle.expired = false;

                 break;

             }

         }

         return bundle;

     }

     private static final boolean isValidBundle(ResourceBundle bundle) {

         return bundle != null && bundle != NONEXISTENT_BUNDLE;

     }

     /**

      * Determines whether any of resource bundles in the parent chain,

      * including the leaf, have expired.

      */

     private static final boolean hasValidParentChain(ResourceBundle bundle) {

         long now = System.currentTimeMillis();

         while (bundle != null) {

             if (bundle.expired) {

                 return false;

             }

             CacheKey key = bundle.cacheKey;

             if (key != null) {

                 long expirationTime = key.expirationTime;

                 if (expirationTime >= 0 && expirationTime <= now) {

                     return false;

                 }

             }

             bundle = bundle.parent;

         }

         return true;

     }

     /**

      * Throw a MissingResourceException with proper message

      */

     private static final void throwMissingResourceException(String baseName,

                                                             Locale locale,

                                                             Throwable cause) {

         // If the cause is a MissingResourceException, avoid creating

         // a long chain. (6355009)

         if (cause instanceof MissingResourceException) {

             cause = null;

         }

         throw new MissingResourceException("Can't find bundle for base name "

                                            + baseName + ", locale " + locale,

                                            baseName + "_" + locale, // className

                                            "",                      // key

                                            cause);

     }

     /**

      * Finds a bundle in the cache. Any expired bundles are marked as

      * `expired' and removed from the cache upon return.

      *

      * @param cacheKey the key to look up the cache

      * @param control the Control to be used for the expiration control

      * @return the cached bundle, or null if the bundle is not found in the

      * cache or its parent has expired. <code>bundle.expire</code> is true

      * upon return if the bundle in the cache has expired.

      */

     private static final ResourceBundle findBundleInCache(CacheKey cacheKey,

                                                           Control control) {

         BundleReference bundleRef = cacheList.get(cacheKey);

         if (bundleRef == null) {

             return null;

         }

         ResourceBundle bundle = bundleRef.get();

         if (bundle == null) {

             return null;

         }

         ResourceBundle p = bundle.parent;

         assert p != NONEXISTENT_BUNDLE;

         // If the parent has expired, then this one must also expire. We

         // check only the immediate parent because the actual loading is

         // done from the root (base) to leaf (child) and the purpose of

         // checking is to propagate expiration towards the leaf. For

         // example, if the requested locale is ja_JP_JP and there are

         // bundles for all of the candidates in the cache, we have a list,

         //

         // base <- ja <- ja_JP <- ja_JP_JP

         //

         // If ja has expired, then it will reload ja and the list becomes a

         // tree.

         //

         // base <- ja (new)

         //  "   <- ja (expired) <- ja_JP <- ja_JP_JP

         //

         // When looking up ja_JP in the cache, it finds ja_JP in the cache

         // which references to the expired ja. Then, ja_JP is marked as

         // expired and removed from the cache. This will be propagated to

         // ja_JP_JP.

         //

         // Now, it's possible, for example, that while loading new ja_JP,

         // someone else has started loading the same bundle and finds the

         // base bundle has expired. Then, what we get from the first

         // getBundle call includes the expired base bundle. However, if

         // someone else didn't start its loading, we wouldn't know if the

         // base bundle has expired at the end of the loading process. The

         // expiration control doesn't guarantee that the returned bundle and

         // its parents haven't expired.

         //

         // We could check the entire parent chain to see if there's any in

         // the chain that has expired. But this process may never end. An

         // extreme case would be that getTimeToLive returns 0 and

         // needsReload always returns true.

         if (p != null && p.expired) {

             assert bundle != NONEXISTENT_BUNDLE;

             bundle.expired = true;

             bundle.cacheKey = null;

             cacheList.remove(cacheKey, bundleRef);

             bundle = null;

         } else {

             CacheKey key = bundleRef.getCacheKey();

             long expirationTime = key.expirationTime;

             if (!bundle.expired && expirationTime >= 0 &&

                 expirationTime <= System.currentTimeMillis()) {

                 // its TTL period has expired.

                 if (bundle != NONEXISTENT_BUNDLE) {

                     // Synchronize here to call needsReload to avoid

                     // redundant concurrent calls for the same bundle.

                     synchronized (bundle) {

                         expirationTime = key.expirationTime;

                         if (!bundle.expired && expirationTime >= 0 &&

                             expirationTime <= System.currentTimeMillis()) {

                             try {

                                 bundle.expired = control.needsReload(key.getName(),

                                                                      key.getLocale(),

                                                                      key.getFormat(),

                                                                      key.getLoader(),

                                                                      bundle,

                                                                      key.loadTime);

                             } catch (Exception e) {

                                 cacheKey.setCause(e);

                             }

                             if (bundle.expired) {

                                 // If the bundle needs to be reloaded, then

                                 // remove the bundle from the cache, but

                                 // return the bundle with the expired flag

                                 // on.

                                 bundle.cacheKey = null;

                                 cacheList.remove(cacheKey, bundleRef);

                             } else {

                                 // Update the expiration control info. and reuse

                                 // the same bundle instance

                                 setExpirationTime(key, control);

                             }

                         }

                     }

                 } else {

                     // We just remove NONEXISTENT_BUNDLE from the cache.

                     cacheList.remove(cacheKey, bundleRef);

                     bundle = null;

                 }

             }

         }

         return bundle;

     }

     /**

      * Put a new bundle in the cache.

      *

      * @param cacheKey the key for the resource bundle

      * @param bundle the resource bundle to be put in the cache

      * @return the ResourceBundle for the cacheKey; if someone has put

      * the bundle before this call, the one found in the cache is

      * returned.

      */

     private static final ResourceBundle putBundleInCache(CacheKey cacheKey,

                                                          ResourceBundle bundle,

                                                          Control control) {

         setExpirationTime(cacheKey, control);

         if (cacheKey.expirationTime != Control.TTL_DONT_CACHE) {

             CacheKey key = (CacheKey) cacheKey.clone();

             BundleReference bundleRef = new BundleReference(bundle, referenceQueue, key);

             bundle.cacheKey = key;

             // Put the bundle in the cache if it's not been in the cache.

             BundleReference result = cacheList.putIfAbsent(key, bundleRef);

             // If someone else has put the same bundle in the cache before

             // us and it has not expired, we should use the one in the cache.

             if (result != null) {

                 ResourceBundle rb = result.get();

                 if (rb != null && !rb.expired) {

                     // Clear the back link to the cache key

                     bundle.cacheKey = null;

                     bundle = rb;

                     // Clear the reference in the BundleReference so that

                     // it won't be enqueued.

                     bundleRef.clear();

                 } else {

                     // Replace the invalid (garbage collected or expired)

                     // instance with the valid one.

                     cacheList.put(key, bundleRef);

                 }

             }

         }

         return bundle;

     }

     private static final void setExpirationTime(CacheKey cacheKey, Control control) {

         long ttl = control.getTimeToLive(cacheKey.getName(),

                                          cacheKey.getLocale());

         if (ttl >= 0) {

             // If any expiration time is specified, set the time to be

             // expired in the cache.

             long now = System.currentTimeMillis();

             cacheKey.loadTime = now;

             cacheKey.expirationTime = now + ttl;

         } else if (ttl >= Control.TTL_NO_EXPIRATION_CONTROL) {

             cacheKey.expirationTime = ttl;

         } else {

             throw new IllegalArgumentException("Invalid Control: TTL=" + ttl);

         }

     }

     /**

      * Removes all resource bundles from the cache that have been loaded

      * using the caller's class loader.

      *

      * @since 1.6

      * @see ResourceBundle.Control#getTimeToLive(String,Locale)

      */

     public static final void clearCache() {

         clearCache(getLoader());

     }

     /**

      * Removes all resource bundles from the cache that have been loaded

      * using the given class loader.

      *

      * @param loader the class loader

      * @exception NullPointerException if <code>loader</code> is null

      * @since 1.6

      * @see ResourceBundle.Control#getTimeToLive(String,Locale)

      */

     public static final void clearCache(ClassLoader loader) {

         if (loader == null) {

             throw new NullPointerException();

         }

         Set<CacheKey> set = cacheList.keySet();

         for (CacheKey key : set) {

             if (key.getLoader() == loader) {

                 set.remove(key);

             }

         }

     }

     /**

      * Gets an object for the given key from this resource bundle.

      * Returns null if this resource bundle does not contain an

      * object for the given key.

      *

      * @param key the key for the desired object

      * @exception NullPointerException if <code>key</code> is <code>null</code>

      * @return the object for the given key, or null

      */

     protected abstract Object handleGetObject(String key);

     /**

      * Returns an enumeration of the keys.

      *

      * @return an <code>Enumeration</code> of the keys contained in

      *         this <code>ResourceBundle</code> and its parent bundles.

      */

     public abstract Enumeration<String> getKeys();

     /**

      * Determines whether the given <code>key</code> is contained in

      * this <code>ResourceBundle</code> or its parent bundles.

      *

      * @param key

      *        the resource <code>key</code>

      * @return <code>true</code> if the given <code>key</code> is

      *        contained in this <code>ResourceBundle</code> or its

      *        parent bundles; <code>false</code> otherwise.

      * @exception NullPointerException

      *         if <code>key</code> is <code>null</code>

      * @since 1.6

      */

     public boolean containsKey(String key) {

         if (key == null) {

             throw new NullPointerException();

         }

         for (ResourceBundle rb = this; rb != null; rb = rb.parent) {

             if (rb.handleKeySet().contains(key)) {

                 return true;

             }

         }

         return false;

     }

     /**

      * Returns a <code>Set</code> of all keys contained in this

      * <code>ResourceBundle</code> and its parent bundles.

      *

      * @return a <code>Set</code> of all keys contained in this

      *         <code>ResourceBundle</code> and its parent bundles.

      * @since 1.6

      */

     public Set<String> keySet() {

         Set<String> keys = new HashSet<>();

         for (ResourceBundle rb = this; rb != null; rb = rb.parent) {

             keys.addAll(rb.handleKeySet());

         }

         return keys;

     }

     /**

      * Returns a <code>Set</code> of the keys contained <em>only</em>

      * in this <code>ResourceBundle</code>.

      *

      * <p>The default implementation returns a <code>Set</code> of the

      * keys returned by the {@link #getKeys() getKeys} method except

      * for the ones for which the {@link #handleGetObject(String)

      * handleGetObject} method returns <code>null</code>. Once the

      * <code>Set</code> has been created, the value is kept in this

      * <code>ResourceBundle</code> in order to avoid producing the

      * same <code>Set</code> in subsequent calls. Subclasses can

      * override this method for faster handling.

      *

      * @return a <code>Set</code> of the keys contained only in this

      *        <code>ResourceBundle</code>

      * @since 1.6

      */

     protected Set<String> handleKeySet() {

         if (keySet == null) {

             synchronized (this) {

                 if (keySet == null) {

                     Set<String> keys = new HashSet<>();

                     Enumeration<String> enumKeys = getKeys();

                     while (enumKeys.hasMoreElements()) {

                         String key = enumKeys.nextElement();

                         if (handleGetObject(key) != null) {

                             keys.add(key);

                         }

                     }

                     keySet = keys;

                 }

             }

         }

         return keySet;

     }

     /**

      * <code>ResourceBundle.Control</code> defines a set of callback methods

      * that are invoked by the {@link ResourceBundle#getBundle(String,

      * Locale, ClassLoader, Control) ResourceBundle.getBundle} factory

      * methods during the bundle loading process. In other words, a

      * <code>ResourceBundle.Control</code> collaborates with the factory

      * methods for loading resource bundles. The default implementation of

      * the callback methods provides the information necessary for the

      * factory methods to perform the <a

      * href="./ResourceBundle.html#default_behavior">default behavior</a>.

      *

      * <p>In addition to the callback methods, the {@link

      * #toBundleName(String, Locale) toBundleName} and {@link

      * #toResourceName(String, String) toResourceName} methods are defined

      * primarily for convenience in implementing the callback

      * methods. However, the <code>toBundleName</code> method could be

      * overridden to provide different conventions in the organization and

      * packaging of localized resources.  The <code>toResourceName</code>

      * method is <code>final</code> to avoid use of wrong resource and class

      * name separators.

      *

      * <p>Two factory methods, {@link #getControl(List)} and {@link

      * #getNoFallbackControl(List)}, provide

      * <code>ResourceBundle.Control</code> instances that implement common

      * variations of the default bundle loading process.

      *

      * <p>The formats returned by the {@link Control#getFormats(String)

      * getFormats} method and candidate locales returned by the {@link

      * ResourceBundle.Control#getCandidateLocales(String, Locale)

      * getCandidateLocales} method must be consistent in all

      * <code>ResourceBundle.getBundle</code> invocations for the same base

      * bundle. Otherwise, the <code>ResourceBundle.getBundle</code> methods

      * may return unintended bundles. For example, if only

      * <code>"java.class"</code> is returned by the <code>getFormats</code>

      * method for the first call to <code>ResourceBundle.getBundle</code>

      * and only <code>"java.properties"</code> for the second call, then the

      * second call will return the class-based one that has been cached

      * during the first call.

      *

      * <p>A <code>ResourceBundle.Control</code> instance must be thread-safe

      * if it's simultaneously used by multiple threads.

      * <code>ResourceBundle.getBundle</code> does not synchronize to call

      * the <code>ResourceBundle.Control</code> methods. The default

      * implementations of the methods are thread-safe.

      *

      * <p>Applications can specify <code>ResourceBundle.Control</code>

      * instances returned by the <code>getControl</code> factory methods or

      * created from a subclass of <code>ResourceBundle.Control</code> to

      * customize the bundle loading process. The following are examples of

      * changing the default bundle loading process.

      *

      * <p><b>Example 1</b>

      *

      * <p>The following code lets <code>ResourceBundle.getBundle</code> look

      * up only properties-based resources.

      *

      * <pre>

      * import java.util.*;

      * import static java.util.ResourceBundle.Control.*;

      * ...

      * ResourceBundle bundle =

      *   ResourceBundle.getBundle("MyResources", new Locale("fr", "CH"),

      *                            ResourceBundle.Control.getControl(FORMAT_PROPERTIES));

      * </pre>

      *

      * Given the resource bundles in the <a

      * href="./ResourceBundle.html#default_behavior_example">example</a> in

      * the <code>ResourceBundle.getBundle</code> description, this

      * <code>ResourceBundle.getBundle</code> call loads

      * <code>MyResources_fr_CH.properties</code> whose parent is

      * <code>MyResources_fr.properties</code> whose parent is

      * <code>MyResources.properties</code>. (<code>MyResources_fr_CH.properties</code>

      * is not hidden, but <code>MyResources_fr_CH.class</code> is.)

      *

      * <p><b>Example 2</b>

      *

      * <p>The following is an example of loading XML-based bundles

      * using {@link Properties#loadFromXML(java.io.InputStream)

      * Properties.loadFromXML}.

      *

      * <pre>

      * ResourceBundle rb = ResourceBundle.getBundle("Messages",

      *     new ResourceBundle.Control() {

      *         public List<String> getFormats(String baseName) {

      *             if (baseName == null)

      *                 throw new NullPointerException();

      *             return Arrays.asList("xml");

      *         }

      *         public ResourceBundle newBundle(String baseName,

      *                                         Locale locale,

      *                                         String format,

      *                                         ClassLoader loader,

      *                                         boolean reload)

      *                          throws IllegalAccessException,

      *                                 InstantiationException,

      *                                 IOException {

      *             if (baseName == null || locale == null

      *                   || format == null || loader == null)

      *                 throw new NullPointerException();

      *             ResourceBundle bundle = null;

      *             if (format.equals("xml")) {

      *                 String bundleName = toBundleName(baseName, locale);

      *                 String resourceName = toResourceName(bundleName, format);

      *                 InputStream stream = null;

      *                 if (reload) {

      *                     URL url = loader.getResource(resourceName);

      *                     if (url != null) {

      *                         URLConnection connection = url.openConnection();

      *                         if (connection != null) {

      *                             // Disable caches to get fresh data for

      *                             // reloading.

      *                             connection.setUseCaches(false);

      *                             stream = connection.getInputStream();

      *                         }

      *                     }

      *                 } else {

      *                     stream = loader.getResourceAsStream(resourceName);

      *                 }

      *                 if (stream != null) {

      *                     BufferedInputStream bis = new BufferedInputStream(stream);

      *                     bundle = new XMLResourceBundle(bis);

      *                     bis.close();

      *                 }

      *             }

      *             return bundle;

      *         }

      *     });

      *

      * ...

      *

      * private static class XMLResourceBundle extends ResourceBundle {

      *     private Properties props;

      *     XMLResourceBundle(InputStream stream) throws IOException {

      *         props = new Properties();

      *         props.loadFromXML(stream);

      *     }

      *     protected Object handleGetObject(String key) {

      *         return props.getProperty(key);

      *     }

      *     public Enumeration<String> getKeys() {

      *         ...

      *     }

      * }

      * </pre>

      *

      * @since 1.6

      */

     public static class Control {

         /**

          * The default format <code>List</code>, which contains the strings

          * <code>"java.class"</code> and <code>"java.properties"</code>, in

          * this order. This <code>List</code> is {@linkplain

          * Collections#unmodifiableList(List) unmodifiable}.

          *

          * @see #getFormats(String)

          */

         public static final List<String> FORMAT_DEFAULT

             = Collections.unmodifiableList(Arrays.asList("java.class",

                                                          "java.properties"));

         /**

          * The class-only format <code>List</code> containing

          * <code>"java.class"</code>. This <code>List</code> is {@linkplain

          * Collections#unmodifiableList(List) unmodifiable}.

          *

          * @see #getFormats(String)

          */

         public static final List<String> FORMAT_CLASS

             = Collections.unmodifiableList(Arrays.asList("java.class"));

         /**

          * The properties-only format <code>List</code> containing

          * <code>"java.properties"</code>. This <code>List</code> is

          * {@linkplain Collections#unmodifiableList(List) unmodifiable}.

          *

          * @see #getFormats(String)

          */

         public static final List<String> FORMAT_PROPERTIES

             = Collections.unmodifiableList(Arrays.asList("java.properties"));

         /**

          * The time-to-live constant for not caching loaded resource bundle

          * instances.

          *

          * @see #getTimeToLive(String, Locale)

          */

         public static final long TTL_DONT_CACHE = -1;

         /**

          * The time-to-live constant for disabling the expiration control

          * for loaded resource bundle instances in the cache.

          *

          * @see #getTimeToLive(String, Locale)

          */

         public static final long TTL_NO_EXPIRATION_CONTROL = -2;

         private static final Control INSTANCE = new Control();

         /**

          * Sole constructor. (For invocation by subclass constructors,

          * typically implicit.)

          */

         protected Control() {

         }

         /**

          * Returns a <code>ResourceBundle.Control</code> in which the {@link

          * #getFormats(String) getFormats} method returns the specified

          * <code>formats</code>. The <code>formats</code> must be equal to

          * one of {@link Control#FORMAT_PROPERTIES}, {@link

          * Control#FORMAT_CLASS} or {@link

          * Control#FORMAT_DEFAULT}. <code>ResourceBundle.Control</code>

          * instances returned by this method are singletons and thread-safe.

          *

          * <p>Specifying {@link Control#FORMAT_DEFAULT} is equivalent to

          * instantiating the <code>ResourceBundle.Control</code> class,

          * except that this method returns a singleton.

          *

          * @param formats

          *        the formats to be returned by the

          *        <code>ResourceBundle.Control.getFormats</code> method

          * @return a <code>ResourceBundle.Control</code> supporting the

          *        specified <code>formats</code>

          * @exception NullPointerException

          *        if <code>formats</code> is <code>null</code>

          * @exception IllegalArgumentException

          *        if <code>formats</code> is unknown

          */

         public static final Control getControl(List<String> formats) {

             if (formats.equals(Control.FORMAT_PROPERTIES)) {

                 return SingleFormatControl.PROPERTIES_ONLY;

             }

             if (formats.equals(Control.FORMAT_CLASS)) {

                 return SingleFormatControl.CLASS_ONLY;

             }

             if (formats.equals(Control.FORMAT_DEFAULT)) {

                 return Control.INSTANCE;

             }

             throw new IllegalArgumentException();

         }

         /**

          * Returns a <code>ResourceBundle.Control</code> in which the {@link

          * #getFormats(String) getFormats} method returns the specified

          * <code>formats</code> and the {@link

          * Control#getFallbackLocale(String, Locale) getFallbackLocale}

          * method returns <code>null</code>. The <code>formats</code> must

          * be equal to one of {@link Control#FORMAT_PROPERTIES}, {@link

          * Control#FORMAT_CLASS} or {@link Control#FORMAT_DEFAULT}.

          * <code>ResourceBundle.Control</code> instances returned by this

          * method are singletons and thread-safe.

          *

          * @param formats

          *        the formats to be returned by the

          *        <code>ResourceBundle.Control.getFormats</code> method

          * @return a <code>ResourceBundle.Control</code> supporting the

          *        specified <code>formats</code> with no fallback

          *        <code>Locale</code> support

          * @exception NullPointerException

          *        if <code>formats</code> is <code>null</code>

          * @exception IllegalArgumentException

          *        if <code>formats</code> is unknown

          */

         public static final Control getNoFallbackControl(List<String> formats) {

             if (formats.equals(Control.FORMAT_DEFAULT)) {

                 return NoFallbackControl.NO_FALLBACK;

             }

             if (formats.equals(Control.FORMAT_PROPERTIES)) {

                 return NoFallbackControl.PROPERTIES_ONLY_NO_FALLBACK;

             }

             if (formats.equals(Control.FORMAT_CLASS)) {

                 return NoFallbackControl.CLASS_ONLY_NO_FALLBACK;

             }

             throw new IllegalArgumentException();

         }

         /**

          * Returns a <code>List</code> of <code>String</code>s containing

          * formats to be used to load resource bundles for the given

          * <code>baseName</code>. The <code>ResourceBundle.getBundle</code>

          * factory method tries to load resource bundles with formats in the

          * order specified by the list. The list returned by this method

          * must have at least one <code>String</code>. The predefined

          * formats are <code>"java.class"</code> for class-based resource

          * bundles and <code>"java.properties"</code> for {@linkplain

          * PropertyResourceBundle properties-based} ones. Strings starting

          * with <code>"java."</code> are reserved for future extensions and

          * must not be used by application-defined formats.

          *

          * <p>It is not a requirement to return an immutable (unmodifiable)

          * <code>List</code>.  However, the returned <code>List</code> must

          * not be mutated after it has been returned by

          * <code>getFormats</code>.

          *

          * <p>The default implementation returns {@link #FORMAT_DEFAULT} so

          * that the <code>ResourceBundle.getBundle</code> factory method

          * looks up first class-based resource bundles, then

          * properties-based ones.

          *

          * @param baseName

          *        the base name of the resource bundle, a fully qualified class

          *        name

          * @return a <code>List</code> of <code>String</code>s containing

          *        formats for loading resource bundles.

          * @exception NullPointerException

          *        if <code>baseName</code> is null

          * @see #FORMAT_DEFAULT

          * @see #FORMAT_CLASS

          * @see #FORMAT_PROPERTIES

          */

         public List<String> getFormats(String baseName) {

             if (baseName == null) {

                 throw new NullPointerException();

             }

             return FORMAT_DEFAULT;

         }

         /**

          * Returns a <code>List</code> of <code>Locale</code>s as candidate

          * locales for <code>baseName</code> and <code>locale</code>. This

          * method is called by the <code>ResourceBundle.getBundle</code>

          * factory method each time the factory method tries finding a

          * resource bundle for a target <code>Locale</code>.

          *

          * <p>The sequence of the candidate locales also corresponds to the

          * runtime resource lookup path (also known as the <I>parent

          * chain</I>), if the corresponding resource bundles for the

          * candidate locales exist and their parents are not defined by

          * loaded resource bundles themselves.  The last element of the list

          * must be a {@linkplain Locale#ROOT root locale} if it is desired to

          * have the base bundle as the terminal of the parent chain.

          *

          * <p>If the given locale is equal to <code>Locale.ROOT</code> (the

          * root locale), a <code>List</code> containing only the root

          * <code>Locale</code> must be returned. In this case, the

          * <code>ResourceBundle.getBundle</code> factory method loads only

          * the base bundle as the resulting resource bundle.

          *

          * <p>It is not a requirement to return an immutable (unmodifiable)

          * <code>List</code>. However, the returned <code>List</code> must not

          * be mutated after it has been returned by

          * <code>getCandidateLocales</code>.

          *

          * <p>The default implementation returns a <code>List</code> containing

          * <code>Locale</code>s using the rules described below.  In the

          * description below, <em>L</em>, <em>S</em>, <em>C</em> and <em>V</em>

          * respectively represent non-empty language, script, country, and

          * variant.  For example, [<em>L</em>, <em>C</em>] represents a

          * <code>Locale</code> that has non-empty values only for language and

          * country.  The form <em>L</em>("xx") represents the (non-empty)

          * language value is "xx".  For all cases, <code>Locale</code>s whose

          * final component values are empty strings are omitted.

          *

          * <ol><li>For an input <code>Locale</code> with an empty script value,

          * append candidate <code>Locale</code>s by omitting the final component

          * one by one as below:

          *

          * <ul>

          * <li> [<em>L</em>, <em>C</em>, <em>V</em>]

          * <li> [<em>L</em>, <em>C</em>]

          * <li> [<em>L</em>]

          * <li> <code>Locale.ROOT</code>

          * </ul>

          *

          * <li>For an input <code>Locale</code> with a non-empty script value,

          * append candidate <code>Locale</code>s by omitting the final component

          * up to language, then append candidates generated from the

          * <code>Locale</code> with country and variant restored:

          *

          * <ul>

          * <li> [<em>L</em>, <em>S</em>, <em>C</em>, <em>V</em>]

          * <li> [<em>L</em>, <em>S</em>, <em>C</em>]

          * <li> [<em>L</em>, <em>S</em>]

          * <li> [<em>L</em>, <em>C</em>, <em>V</em>]

          * <li> [<em>L</em>, <em>C</em>]

          * <li> [<em>L</em>]

          * <li> <code>Locale.ROOT</code>

          * </ul>

          *

          * <li>For an input <code>Locale</code> with a variant value consisting

          * of multiple subtags separated by underscore, generate candidate

          * <code>Locale</code>s by omitting the variant subtags one by one, then

          * insert them after every occurence of <code> Locale</code>s with the

          * full variant value in the original list.  For example, if the

          * the variant consists of two subtags <em>V1</em> and <em>V2</em>:

          *

          * <ul>

          * <li> [<em>L</em>, <em>S</em>, <em>C</em>, <em>V1</em>, <em>V2</em>]

          * <li> [<em>L</em>, <em>S</em>, <em>C</em>, <em>V1</em>]

          * <li> [<em>L</em>, <em>S</em>, <em>C</em>]

          * <li> [<em>L</em>, <em>S</em>]

          * <li> [<em>L</em>, <em>C</em>, <em>V1</em>, <em>V2</em>]

          * <li> [<em>L</em>, <em>C</em>, <em>V1</em>]

          * <li> [<em>L</em>, <em>C</em>]

          * <li> [<em>L</em>]

          * <li> <code>Locale.ROOT</code>

          * </ul>

          *

          * <li>Special cases for Chinese.  When an input <code>Locale</code> has the

          * language "zh" (Chinese) and an empty script value, either "Hans" (Simplified) or

          * "Hant" (Traditional) might be supplied, depending on the country.

          * When the country is "CN" (China) or "SG" (Singapore), "Hans" is supplied.

          * When the country is "HK" (Hong Kong SAR China), "MO" (Macau SAR China),

          * or "TW" (Taiwan), "Hant" is supplied.  For all other countries or when the country

          * is empty, no script is supplied.  For example, for <code>Locale("zh", "CN")

          * </code>, the candidate list will be:

          * <ul>

          * <li> [<em>L</em>("zh"), <em>S</em>("Hans"), <em>C</em>("CN")]

          * <li> [<em>L</em>("zh"), <em>S</em>("Hans")]

          * <li> [<em>L</em>("zh"), <em>C</em>("CN")]

          * <li> [<em>L</em>("zh")]

          * <li> <code>Locale.ROOT</code>

          * </ul>

          *

          * For <code>Locale("zh", "TW")</code>, the candidate list will be:

          * <ul>

          * <li> [<em>L</em>("zh"), <em>S</em>("Hant"), <em>C</em>("TW")]

          * <li> [<em>L</em>("zh"), <em>S</em>("Hant")]

          * <li> [<em>L</em>("zh"), <em>C</em>("TW")]

          * <li> [<em>L</em>("zh")]

          * <li> <code>Locale.ROOT</code>

          * </ul>

          *

          * <li>Special cases for Norwegian.  Both <code>Locale("no", "NO",

          * "NY")</code> and <code>Locale("nn", "NO")</code> represent Norwegian

          * Nynorsk.  When a locale's language is "nn", the standard candidate

          * list is generated up to [<em>L</em>("nn")], and then the following

          * candidates are added:

          *

          * <ul><li> [<em>L</em>("no"), <em>C</em>("NO"), <em>V</em>("NY")]

          * <li> [<em>L</em>("no"), <em>C</em>("NO")]

          * <li> [<em>L</em>("no")]

          * <li> <code>Locale.ROOT</code>

          * </ul>

          *

          * If the locale is exactly <code>Locale("no", "NO", "NY")</code>, it is first

          * converted to <code>Locale("nn", "NO")</code> and then the above procedure is

          * followed.

          *

          * <p>Also, Java treats the language "no" as a synonym of Norwegian

          * Bokm&#xE5;l "nb".  Except for the single case <code>Locale("no",

          * "NO", "NY")</code> (handled above), when an input <code>Locale</code>

          * has language "no" or "nb", candidate <code>Locale</code>s with

          * language code "no" and "nb" are interleaved, first using the

          * requested language, then using its synonym. For example,

          * <code>Locale("nb", "NO", "POSIX")</code> generates the following

          * candidate list:

          *

          * <ul>

          * <li> [<em>L</em>("nb"), <em>C</em>("NO"), <em>V</em>("POSIX")]

          * <li> [<em>L</em>("no"), <em>C</em>("NO"), <em>V</em>("POSIX")]

          * <li> [<em>L</em>("nb"), <em>C</em>("NO")]

          * <li> [<em>L</em>("no"), <em>C</em>("NO")]

          * <li> [<em>L</em>("nb")]

          * <li> [<em>L</em>("no")]

          * <li> <code>Locale.ROOT</code>

          * </ul>

          *

          * <code>Locale("no", "NO", "POSIX")</code> would generate the same list

          * except that locales with "no" would appear before the corresponding

          * locales with "nb".</li>

          *

          * </li>

          * </ol>

          *

          * <p>The default implementation uses an {@link ArrayList} that

          * overriding implementations may modify before returning it to the

          * caller. However, a subclass must not modify it after it has

          * been returned by <code>getCandidateLocales</code>.

          *

          * <p>For example, if the given <code>baseName</code> is "Messages"

          * and the given <code>locale</code> is

          * <code>Locale("ja",&nbsp;"",&nbsp;"XX")</code>, then a

          * <code>List</code> of <code>Locale</code>s:

          * <pre>

          *     Locale("ja", "", "XX")

          *     Locale("ja")

          *     Locale.ROOT

          * </pre>

          * is returned. And if the resource bundles for the "ja" and

          * "" <code>Locale</code>s are found, then the runtime resource

          * lookup path (parent chain) is:

          * <pre>

          *     Messages_ja -> Messages

          * </pre>

          *

          * @param baseName

          *        the base name of the resource bundle, a fully

          *        qualified class name

          * @param locale

          *        the locale for which a resource bundle is desired

          * @return a <code>List</code> of candidate

          *        <code>Locale</code>s for the given <code>locale</code>

          * @exception NullPointerException

          *        if <code>baseName</code> or <code>locale</code> is

          *        <code>null</code>

          */

         public List<Locale> getCandidateLocales(String baseName, Locale locale) {

             if (baseName == null) {

                 throw new NullPointerException();

             }

             return new ArrayList<>(CANDIDATES_CACHE.get(locale.getBaseLocale()));

         }

         private static final CandidateListCache CANDIDATES_CACHE = new CandidateListCache();

         private static class CandidateListCache extends LocaleObjectCache<BaseLocale, List<Locale>> {

             protected List<Locale> createObject(BaseLocale base) {

                 String language = base.getLanguage();

                 String script = base.getScript();

                 String region = base.getRegion();

                 String variant = base.getVariant();

                 // Special handling for Norwegian

                 boolean isNorwegianBokmal = false;

                 boolean isNorwegianNynorsk = false;

                 if (language.equals("no")) {

                     if (region.equals("NO") && variant.equals("NY")) {

                         variant = "";

                         isNorwegianNynorsk = true;

                     } else {

                         isNorwegianBokmal = true;

                     }

                 }

                 if (language.equals("nb") || isNorwegianBokmal) {

                     List<Locale> tmpList = getDefaultList("nb", script, region, variant);

                     // Insert a locale replacing "nb" with "no" for every list entry

                     List<Locale> bokmalList = new LinkedList<>();

                     for (Locale l : tmpList) {

                         bokmalList.add(l);

                         if (l.getLanguage().length() == 0) {

                             break;

                         }

                         bokmalList.add(Locale.getInstance("no", l.getScript(), l.getCountry(),

                                 l.getVariant(), null));

                     }

                     return bokmalList;

                 } else if (language.equals("nn") || isNorwegianNynorsk) {

                     // Insert no_NO_NY, no_NO, no after nn

                     List<Locale> nynorskList = getDefaultList("nn", script, region, variant);

                     int idx = nynorskList.size() - 1;

                     nynorskList.add(idx++, Locale.getInstance("no", "NO", "NY"));

                     nynorskList.add(idx++, Locale.getInstance("no", "NO", ""));

                     nynorskList.add(idx++, Locale.getInstance("no", "", ""));

                     return nynorskList;

                 }

                 // Special handling for Chinese

                 else if (language.equals("zh")) {

                     if (script.length() == 0 && region.length() > 0) {

                         // Supply script for users who want to use zh_Hans/zh_Hant

                         // as bundle names (recommended for Java7+)

                         if (region.equals("TW") || region.equals("HK") || region.equals("MO")) {

                             script = "Hant";

                         } else if (region.equals("CN") || region.equals("SG")) {

                             script = "Hans";

                         }

                     } else if (script.length() > 0 && region.length() == 0) {

                         // Supply region(country) for users who still package Chinese

                         // bundles using old convension.

                         if (script.equals("Hans")) {

                             region = "CN";

                         } else if (script.equals("Hant")) {

                             region = "TW";

                         }

                     }

                 }

                 return getDefaultList(language, script, region, variant);

             }

             private static List<Locale> getDefaultList(String language, String script, String region, String variant) {

                 List<String> variants = null;

                 if (variant.length() > 0) {

                     variants = new LinkedList<>();

                     int idx = variant.length();

                     while (idx != -1) {

                         variants.add(variant.substring(0, idx));

                         idx = variant.lastIndexOf('_', --idx);

                     }

                 }

                 List<Locale> list = new LinkedList<>();

                 if (variants != null) {

                     for (String v : variants) {

                         list.add(Locale.getInstance(language, script, region, v, null));

                     }

                 }

                 if (region.length() > 0) {

                     list.add(Locale.getInstance(language, script, region, "", null));

                 }

                 if (script.length() > 0) {

                     list.add(Locale.getInstance(language, script, "", "", null));

                     // With script, after truncating variant, region and script,

                     // start over without script.

                     if (variants != null) {

                         for (String v : variants) {

                             list.add(Locale.getInstance(language, "", region, v, null));

                         }

                     }

                     if (region.length() > 0) {

                         list.add(Locale.getInstance(language, "", region, "", null));

                     }

                 }

                 if (language.length() > 0) {

                     list.add(Locale.getInstance(language, "", "", "", null));

                 }

                 // Add root locale at the end

                 list.add(Locale.ROOT);

                 return list;

             }

         }

         /**

          * Returns a <code>Locale</code> to be used as a fallback locale for

          * further resource bundle searches by the

          * <code>ResourceBundle.getBundle</code> factory method. This method

          * is called from the factory method every time when no resulting

          * resource bundle has been found for <code>baseName</code> and

          * <code>locale</code>, where locale is either the parameter for

          * <code>ResourceBundle.getBundle</code> or the previous fallback

          * locale returned by this method.

          *

          * <p>The method returns <code>null</code> if no further fallback

          * search is desired.

          *

          * <p>The default implementation returns the {@linkplain

          * Locale#getDefault() default <code>Locale</code>} if the given

          * <code>locale</code> isn't the default one.  Otherwise,

          * <code>null</code> is returned.

          *

          * @param baseName

          *        the base name of the resource bundle, a fully

          *        qualified class name for which

          *        <code>ResourceBundle.getBundle</code> has been

          *        unable to find any resource bundles (except for the

          *        base bundle)

          * @param locale

          *        the <code>Locale</code> for which

          *        <code>ResourceBundle.getBundle</code> has been

          *        unable to find any resource bundles (except for the

          *        base bundle)

          * @return a <code>Locale</code> for the fallback search,

          *        or <code>null</code> if no further fallback search

          *        is desired.

          * @exception NullPointerException

          *        if <code>baseName</code> or <code>locale</code>

          *        is <code>null</code>

          */

         public Locale getFallbackLocale(String baseName, Locale locale) {

             if (baseName == null) {

                 throw new NullPointerException();

             }

             Locale defaultLocale = Locale.getDefault();

             return locale.equals(defaultLocale) ? null : defaultLocale;

         }

         /**

          * Instantiates a resource bundle for the given bundle name of the

          * given format and locale, using the given class loader if

          * necessary. This method returns <code>null</code> if there is no

          * resource bundle available for the given parameters. If a resource

          * bundle can't be instantiated due to an unexpected error, the

          * error must be reported by throwing an <code>Error</code> or

          * <code>Exception</code> rather than simply returning

          * <code>null</code>.

          *

          * <p>If the <code>reload</code> flag is <code>true</code>, it

          * indicates that this method is being called because the previously

          * loaded resource bundle has expired.

          *

          * <p>The default implementation instantiates a

          * <code>ResourceBundle</code> as follows.

          *

          * <ul>

          *

          * <li>The bundle name is obtained by calling {@link

          * #toBundleName(String, Locale) toBundleName(baseName,

          * locale)}.</li>

          *

          * <li>If <code>format</code> is <code>"java.class"</code>, the

          * {@link Class} specified by the bundle name is loaded by calling

          * {@link ClassLoader#loadClass(String)}. Then, a

          * <code>ResourceBundle</code> is instantiated by calling {@link

          * Class#newInstance()}.  Note that the <code>reload</code> flag is

          * ignored for loading class-based resource bundles in this default

          * implementation.</li>

          *

          * <li>If <code>format</code> is <code>"java.properties"</code>,

          * {@link #toResourceName(String, String) toResourceName(bundlename,

          * "properties")} is called to get the resource name.

          * If <code>reload</code> is <code>true</code>, {@link

          * ClassLoader#getResource(String) load.getResource} is called

          * to get a {@link URL} for creating a {@link

          * URLConnection}. This <code>URLConnection</code> is used to

          * {@linkplain URLConnection#setUseCaches(boolean) disable the

          * caches} of the underlying resource loading layers,

          * and to {@linkplain URLConnection#getInputStream() get an

          * <code>InputStream</code>}.

          * Otherwise, {@link ClassLoader#getResourceAsStream(String)

          * loader.getResourceAsStream} is called to get an {@link

          * InputStream}. Then, a {@link

          * PropertyResourceBundle} is constructed with the

          * <code>InputStream</code>.</li>

          *

          * <li>If <code>format</code> is neither <code>"java.class"</code>

          * nor <code>"java.properties"</code>, an

          * <code>IllegalArgumentException</code> is thrown.</li>

          *

          * </ul>

          *

          * @param baseName

          *        the base bundle name of the resource bundle, a fully

          *        qualified class name

          * @param locale

          *        the locale for which the resource bundle should be

          *        instantiated

          * @param format

          *        the resource bundle format to be loaded

          * @param loader

          *        the <code>ClassLoader</code> to use to load the bundle

          * @param reload

          *        the flag to indicate bundle reloading; <code>true</code>

          *        if reloading an expired resource bundle,

          *        <code>false</code> otherwise

          * @return the resource bundle instance,

          *        or <code>null</code> if none could be found.

          * @exception NullPointerException

          *        if <code>bundleName</code>, <code>locale</code>,

          *        <code>format</code>, or <code>loader</code> is

          *        <code>null</code>, or if <code>null</code> is returned by

          *        {@link #toBundleName(String, Locale) toBundleName}

          * @exception IllegalArgumentException

          *        if <code>format</code> is unknown, or if the resource

          *        found for the given parameters contains malformed data.

          * @exception ClassCastException

          *        if the loaded class cannot be cast to <code>ResourceBundle</code>

          * @exception IllegalAccessException

          *        if the class or its nullary constructor is not

          *        accessible.

          * @exception InstantiationException

          *        if the instantiation of a class fails for some other

          *        reason.

          * @exception ExceptionInInitializerError

          *        if the initialization provoked by this method fails.

          * @exception SecurityException

          *        If a security manager is present and creation of new

          *        instances is denied. See {@link Class#newInstance()}

          *        for details.

          * @exception IOException

          *        if an error occurred when reading resources using

          *        any I/O operations

          */

         public ResourceBundle newBundle(String baseName, Locale locale, String format,

                                         ClassLoader loader, boolean reload)

                     throws IllegalAccessException, InstantiationException, IOException {

             String bundleName = toBundleName(baseName, locale);

             ResourceBundle bundle = null;

             if (format.equals("java.class")) {

                 try {

                     Class<? extends ResourceBundle> bundleClass

                         = (Class<? extends ResourceBundle>)loader.loadClass(bundleName);

                     // If the class isn't a ResourceBundle subclass, throw a

                     // ClassCastException.

                     if (ResourceBundle.class.isAssignableFrom(bundleClass)) {

                         bundle = bundleClass.newInstance();

                     } else {

                         throw new ClassCastException(bundleClass.getName()

                                      + " cannot be cast to ResourceBundle");

                     }

                 } catch (ClassNotFoundException e) {

                 }

             } else if (format.equals("java.properties")) {

                 final String resourceName = toResourceName(bundleName, "properties");

                 final ClassLoader classLoader = loader;

                 final boolean reloadFlag = reload;

                 InputStream stream = null;

                 try {

                     stream = AccessController.doPrivileged(

                         new PrivilegedExceptionAction<InputStream>() {

                             public InputStream run() throws IOException {

                                 InputStream is = null;

                                 if (reloadFlag) {

                                     URL url = classLoader.getResource(resourceName);

                                     if (url != null) {

                                         URLConnection connection = url.openConnection();

                                         if (connection != null) {

                                             // Disable caches to get fresh data for

                                             // reloading.

                                             connection.setUseCaches(false);

                                             is = connection.getInputStream();

                                         }

                                     }

                                 } else {

                                     is = classLoader.getResourceAsStream(resourceName);

                                 }

                                 return is;

                             }

                         });

                 } catch (PrivilegedActionException e) {

                     throw (IOException) e.getException();

                 }

                 if (stream != null) {

                     try {

                         bundle = new PropertyResourceBundle(stream);

                     } finally {

                         stream.close();

                     }

                 }

             } else {

                 throw new IllegalArgumentException("unknown format: " + format);

             }

             return bundle;

         }

         /**

          * Returns the time-to-live (TTL) value for resource bundles that

          * are loaded under this

          * <code>ResourceBundle.Control</code>. Positive time-to-live values

          * specify the number of milliseconds a bundle can remain in the

          * cache without being validated against the source data from which

          * it was constructed. The value 0 indicates that a bundle must be

          * validated each time it is retrieved from the cache. {@link

          * #TTL_DONT_CACHE} specifies that loaded resource bundles are not

          * put in the cache. {@link #TTL_NO_EXPIRATION_CONTROL} specifies

          * that loaded resource bundles are put in the cache with no

          * expiration control.

          *

          * <p>The expiration affects only the bundle loading process by the

          * <code>ResourceBundle.getBundle</code> factory method.  That is,

          * if the factory method finds a resource bundle in the cache that

          * has expired, the factory method calls the {@link

          * #needsReload(String, Locale, String, ClassLoader, ResourceBundle,

          * long) needsReload} method to determine whether the resource

          * bundle needs to be reloaded. If <code>needsReload</code> returns

          * <code>true</code>, the cached resource bundle instance is removed

          * from the cache. Otherwise, the instance stays in the cache,

          * updated with the new TTL value returned by this method.

          *

          * <p>All cached resource bundles are subject to removal from the

          * cache due to memory constraints of the runtime environment.

          * Returning a large positive value doesn't mean to lock loaded

          * resource bundles in the cache.

          *

          * <p>The default implementation returns {@link #TTL_NO_EXPIRATION_CONTROL}.

          *