/*

 * Copyright (c) 1994, 2010, 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.

 */

package java.lang;

import java.lang.reflect.Array;

import java.lang.reflect.GenericArrayType;

import java.lang.reflect.Member;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.lang.reflect.Constructor;

import java.lang.reflect.GenericDeclaration;

import java.lang.reflect.Modifier;

import java.lang.reflect.Type;

import java.lang.reflect.TypeVariable;

import java.lang.reflect.InvocationTargetException;

import java.lang.ref.SoftReference;

import java.io.InputStream;

import java.io.ObjectStreamField;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.HashSet;

import java.util.Iterator;

import java.util.List;

import java.util.LinkedList;

import java.util.LinkedHashSet;

import java.util.Set;

import java.util.Map;

import java.util.HashMap;

import sun.misc.Unsafe;

import sun.reflect.ConstantPool;

import sun.reflect.Reflection;

import sun.reflect.ReflectionFactory;

import sun.reflect.SignatureIterator;

import sun.reflect.generics.factory.CoreReflectionFactory;

import sun.reflect.generics.factory.GenericsFactory;

import sun.reflect.generics.repository.ClassRepository;

import sun.reflect.generics.repository.MethodRepository;

import sun.reflect.generics.repository.ConstructorRepository;

import sun.reflect.generics.scope.ClassScope;

import sun.security.util.SecurityConstants;

import java.lang.annotation.Annotation;

import sun.reflect.annotation.*;

/**

 * Instances of the class {@code Class} represent classes and

 * interfaces in a running Java application.  An enum is a kind of

 * class and an annotation is a kind of interface.  Every array also

 * belongs to a class that is reflected as a {@code Class} object

 * that is shared by all arrays with the same element type and number

 * of dimensions.  The primitive Java types ({@code boolean},

 * {@code byte}, {@code char}, {@code short},

 * {@code int}, {@code long}, {@code float}, and

 * {@code double}), and the keyword {@code void} are also

 * represented as {@code Class} objects.

 *

 * <p> {@code Class} has no public constructor. Instead {@code Class}

 * objects are constructed automatically by the Java Virtual Machine as classes

 * are loaded and by calls to the {@code defineClass} method in the class

 * loader.

 *

 * <p> The following example uses a {@code Class} object to print the

 * class name of an object:

 *

 * <p> <blockquote><pre>

 *     void printClassName(Object obj) {

 *         System.out.println("The class of " + obj +

 *                            " is " + obj.getClass().getName());

 *     }

 * </pre></blockquote>

 *

 * <p> It is also possible to get the {@code Class} object for a named

 * type (or for void) using a class literal.  See Section 15.8.2 of

 * <cite>The Java&trade; Language Specification</cite>.

 * For example:

 *

 * <p> <blockquote>

 *     {@code System.out.println("The name of class Foo is: "+Foo.class.getName());}

 * </blockquote>

 *

 * @param <T> the type of the class modeled by this {@code Class}

 * object.  For example, the type of {@code String.class} is {@code

 * Class<String>}.  Use {@code Class<?>} if the class being modeled is

 * unknown.

 *

 * @author  unascribed

 * @see     java.lang.ClassLoader#defineClass(byte[], int, int)

 * @since   JDK1.0

 */

public final

    class Class<T> implements java.io.Serializable,

                              java.lang.reflect.GenericDeclaration,

                              java.lang.reflect.Type,

                              java.lang.reflect.AnnotatedElement {

    private static final int ANNOTATION= 0x00002000;

    private static final int ENUM      = 0x00004000;

    private static final int SYNTHETIC = 0x00001000;

    private static native void registerNatives();

    static {

        registerNatives();

    }

    /*

     * Constructor. Only the Java Virtual Machine creates Class

     * objects.

     */

    private Class() {}

    /**

     * Converts the object to a string. The string representation is the

     * string "class" or "interface", followed by a space, and then by the

     * fully qualified name of the class in the format returned by

     * {@code getName}.  If this {@code Class} object represents a

     * primitive type, this method returns the name of the primitive type.  If

     * this {@code Class} object represents void this method returns

     * "void".

     *

     * @return a string representation of this class object.

     */

    public String toString() {

        return (isInterface() ? "interface " : (isPrimitive() ? "" : "class "))

            + getName();

    }

    /**

     * Returns the {@code Class} object associated with the class or

     * interface with the given string name.  Invoking this method is

     * equivalent to:

     *

     * <blockquote>

     *  {@code Class.forName(className, true, currentLoader)}

     * </blockquote>

     *

     * where {@code currentLoader} denotes the defining class loader of

     * the current class.

     *

     * <p> For example, the following code fragment returns the

     * runtime {@code Class} descriptor for the class named

     * {@code java.lang.Thread}:

     *

     * <blockquote>

     *   {@code Class t = Class.forName("java.lang.Thread")}

     * </blockquote>

     * <p>

     * A call to {@code forName("X")} causes the class named

     * {@code X} to be initialized.

     *

     * @param      className   the fully qualified name of the desired class.

     * @return     the {@code Class} object for the class with the

     *             specified name.

     * @exception LinkageError if the linkage fails

     * @exception ExceptionInInitializerError if the initialization provoked

     *            by this method fails

     * @exception ClassNotFoundException if the class cannot be located

     */

    public static Class<?> forName(String className)

                throws ClassNotFoundException {

        return forName0(className, true, ClassLoader.getCallerClassLoader());

    }

    /**

     * Returns the {@code Class} object associated with the class or

     * interface with the given string name, using the given class loader.

     * Given the fully qualified name for a class or interface (in the same

     * format returned by {@code getName}) this method attempts to

     * locate, load, and link the class or interface.  The specified class

     * loader is used to load the class or interface.  If the parameter

     * {@code loader} is null, the class is loaded through the bootstrap

     * class loader.  The class is initialized only if the

     * {@code initialize} parameter is {@code true} and if it has

     * not been initialized earlier.

     *

     * <p> If {@code name} denotes a primitive type or void, an attempt

     * will be made to locate a user-defined class in the unnamed package whose

     * name is {@code name}. Therefore, this method cannot be used to

     * obtain any of the {@code Class} objects representing primitive

     * types or void.

     *

     * <p> If {@code name} denotes an array class, the component type of

     * the array class is loaded but not initialized.

     *

     * <p> For example, in an instance method the expression:

     *

     * <blockquote>

     *  {@code Class.forName("Foo")}

     * </blockquote>

     *

     * is equivalent to:

     *

     * <blockquote>

     *  {@code Class.forName("Foo", true, this.getClass().getClassLoader())}

     * </blockquote>

     *

     * Note that this method throws errors related to loading, linking or

     * initializing as specified in Sections 12.2, 12.3 and 12.4 of <em>The

     * Java Language Specification</em>.

     * Note that this method does not check whether the requested class

     * is accessible to its caller.

     *

     * <p> If the {@code loader} is {@code null}, and a security

     * manager is present, and the caller's class loader is not null, then this

     * method calls the security manager's {@code checkPermission} method

     * with a {@code RuntimePermission("getClassLoader")} permission to

     * ensure it's ok to access the bootstrap class loader.

     *

     * @param name       fully qualified name of the desired class

     * @param initialize whether the class must be initialized

     * @param loader     class loader from which the class must be loaded

     * @return           class object representing the desired class

     *

     * @exception LinkageError if the linkage fails

     * @exception ExceptionInInitializerError if the initialization provoked

     *            by this method fails

     * @exception ClassNotFoundException if the class cannot be located by

     *            the specified class loader

     *

     * @see       java.lang.Class#forName(String)

     * @see       java.lang.ClassLoader

     * @since     1.2

     */

    public static Class<?> forName(String name, boolean initialize,

                                   ClassLoader loader)

        throws ClassNotFoundException

    {

        if (loader == null) {

            SecurityManager sm = System.getSecurityManager();

            if (sm != null) {

                ClassLoader ccl = ClassLoader.getCallerClassLoader();

                if (ccl != null) {

                    sm.checkPermission(

                        SecurityConstants.GET_CLASSLOADER_PERMISSION);

                }

            }

        }

        return forName0(name, initialize, loader);

    }

    /** Called after security checks have been made. */

    private static native Class<?> forName0(String name, boolean initialize,

                                            ClassLoader loader)

        throws ClassNotFoundException;

    /**

     * Creates a new instance of the class represented by this {@code Class}

     * object.  The class is instantiated as if by a {@code new}

     * expression with an empty argument list.  The class is initialized if it

     * has not already been initialized.

     *

     * <p>Note that this method propagates any exception thrown by the

     * nullary constructor, including a checked exception.  Use of

     * this method effectively bypasses the compile-time exception

     * checking that would otherwise be performed by the compiler.

     * The {@link

     * java.lang.reflect.Constructor#newInstance(java.lang.Object...)

     * Constructor.newInstance} method avoids this problem by wrapping

     * any exception thrown by the constructor in a (checked) {@link

     * java.lang.reflect.InvocationTargetException}.

     *

     * @return     a newly allocated instance of the class represented by this

     *             object.

     * @exception  IllegalAccessException  if the class or its nullary

     *               constructor is not accessible.

     * @exception  InstantiationException

     *               if this {@code Class} represents an abstract class,

     *               an interface, an array class, a primitive type, or void;

     *               or if the class has no nullary constructor;

     *               or if the instantiation fails for some other reason.

     * @exception  ExceptionInInitializerError if the initialization

     *               provoked by this method fails.

     * @exception  SecurityException

     *             If a security manager, <i>s</i>, is present and any of the

     *             following conditions is met:

     *

     *             <ul>

     *

     *             <li> invocation of

     *             {@link SecurityManager#checkMemberAccess

     *             s.checkMemberAccess(this, Member.PUBLIC)} denies

     *             creation of new instances of this class

     *

     *             <li> the caller's class loader is not the same as or an

     *             ancestor of the class loader for the current class and

     *             invocation of {@link SecurityManager#checkPackageAccess

     *             s.checkPackageAccess()} denies access to the package

     *             of this class

     *

     *             </ul>

     *

     */

    public T newInstance()

        throws InstantiationException, IllegalAccessException

    {

        if (System.getSecurityManager() != null) {

            checkMemberAccess(Member.PUBLIC, ClassLoader.getCallerClassLoader());

        }

        return newInstance0();

    }

    private T newInstance0()

        throws InstantiationException, IllegalAccessException

    {

        // NOTE: the following code may not be strictly correct under

        // the current Java memory model.

        // Constructor lookup

        if (cachedConstructor == null) {

            if (this == Class.class) {

                throw new IllegalAccessException(

                    "Can not call newInstance() on the Class for java.lang.Class"

                );

            }

            try {

                Class<?>[] empty = {};

                final Constructor<T> c = getConstructor0(empty, Member.DECLARED);

                // Disable accessibility checks on the constructor

                // since we have to do the security check here anyway

                // (the stack depth is wrong for the Constructor's

                // security check to work)

                java.security.AccessController.doPrivileged(

                    new java.security.PrivilegedAction<Void>() {

                        public Void run() {

                                c.setAccessible(true);

                                return null;

                            }

                        });

                cachedConstructor = c;

            } catch (NoSuchMethodException e) {

                throw new InstantiationException(getName());

            }

        }

        Constructor<T> tmpConstructor = cachedConstructor;

        // Security check (same as in java.lang.reflect.Constructor)

        int modifiers = tmpConstructor.getModifiers();

        if (!Reflection.quickCheckMemberAccess(this, modifiers)) {

            Class<?> caller = Reflection.getCallerClass(3);

            if (newInstanceCallerCache != caller) {

                Reflection.ensureMemberAccess(caller, this, null, modifiers);

                newInstanceCallerCache = caller;

            }

        }

        // Run constructor

        try {

            return tmpConstructor.newInstance((Object[])null);

        } catch (InvocationTargetException e) {

            Unsafe.getUnsafe().throwException(e.getTargetException());

            // Not reached

            return null;

        }

    }

    private volatile transient Constructor<T> cachedConstructor;

    private volatile transient Class<?>       newInstanceCallerCache;

    /**

     * Determines if the specified {@code Object} is assignment-compatible

     * with the object represented by this {@code Class}.  This method is

     * the dynamic equivalent of the Java language {@code instanceof}

     * operator. The method returns {@code true} if the specified

     * {@code Object} argument is non-null and can be cast to the

     * reference type represented by this {@code Class} object without

     * raising a {@code ClassCastException.} It returns {@code false}

     * otherwise.

     *

     * <p> Specifically, if this {@code Class} object represents a

     * declared class, this method returns {@code true} if the specified

     * {@code Object} argument is an instance of the represented class (or

     * of any of its subclasses); it returns {@code false} otherwise. If

     * this {@code Class} object represents an array class, this method

     * returns {@code true} if the specified {@code Object} argument

     * can be converted to an object of the array class by an identity

     * conversion or by a widening reference conversion; it returns

     * {@code false} otherwise. If this {@code Class} object

     * represents an interface, this method returns {@code true} if the

     * class or any superclass of the specified {@code Object} argument

     * implements this interface; it returns {@code false} otherwise. If

     * this {@code Class} object represents a primitive type, this method

     * returns {@code false}.

     *

     * @param   obj the object to check

     * @return  true if {@code obj} is an instance of this class

     *

     * @since JDK1.1

     */

    public native boolean isInstance(Object obj);

    /**

     * Determines if the class or interface represented by this

     * {@code Class} object is either the same as, or is a superclass or

     * superinterface of, the class or interface represented by the specified

     * {@code Class} parameter. It returns {@code true} if so;

     * otherwise it returns {@code false}. If this {@code Class}

     * object represents a primitive type, this method returns

     * {@code true} if the specified {@code Class} parameter is

     * exactly this {@code Class} object; otherwise it returns

     * {@code false}.

     *

     * <p> Specifically, this method tests whether the type represented by the

     * specified {@code Class} parameter can be converted to the type

     * represented by this {@code Class} object via an identity conversion

     * or via a widening reference conversion. See <em>The Java Language

     * Specification</em>, sections 5.1.1 and 5.1.4 , for details.

     *

     * @param cls the {@code Class} object to be checked

     * @return the {@code boolean} value indicating whether objects of the

     * type {@code cls} can be assigned to objects of this class

     * @exception NullPointerException if the specified Class parameter is

     *            null.

     * @since JDK1.1

     */

    public native boolean isAssignableFrom(Class<?> cls);

    /**

     * Determines if the specified {@code Class} object represents an

     * interface type.

     *

     * @return  {@code true} if this object represents an interface;

     *          {@code false} otherwise.

     */

    public native boolean isInterface();

    /**

     * Determines if this {@code Class} object represents an array class.

     *

     * @return  {@code true} if this object represents an array class;

     *          {@code false} otherwise.

     * @since   JDK1.1

     */

    public native boolean isArray();

    /**

     * Determines if the specified {@code Class} object represents a

     * primitive type.

     *

     * <p> There are nine predefined {@code Class} objects to represent

     * the eight primitive types and void.  These are created by the Java

     * Virtual Machine, and have the same names as the primitive types that

     * they represent, namely {@code boolean}, {@code byte},

     * {@code char}, {@code short}, {@code int},

     * {@code long}, {@code float}, and {@code double}.

     *

     * <p> These objects may only be accessed via the following public static

     * final variables, and are the only {@code Class} objects for which

     * this method returns {@code true}.

     *

     * @return true if and only if this class represents a primitive type

     *

     * @see     java.lang.Boolean#TYPE

     * @see     java.lang.Character#TYPE

     * @see     java.lang.Byte#TYPE

     * @see     java.lang.Short#TYPE

     * @see     java.lang.Integer#TYPE

     * @see     java.lang.Long#TYPE

     * @see     java.lang.Float#TYPE

     * @see     java.lang.Double#TYPE

     * @see     java.lang.Void#TYPE

     * @since JDK1.1

     */

    public native boolean isPrimitive();

    /**

     * Returns true if this {@code Class} object represents an annotation

     * type.  Note that if this method returns true, {@link #isInterface()}

     * would also return true, as all annotation types are also interfaces.

     *

     * @return {@code true} if this class object represents an annotation

     *      type; {@code false} otherwise

     * @since 1.5

     */

    public boolean isAnnotation() {

        return (getModifiers() & ANNOTATION) != 0;

    }

    /**

     * Returns {@code true} if this class is a synthetic class;

     * returns {@code false} otherwise.

     * @return {@code true} if and only if this class is a synthetic class as

     *         defined by the Java Language Specification.

     * @since 1.5

     */

    public boolean isSynthetic() {

        return (getModifiers() & SYNTHETIC) != 0;

    }

    /**

     * Returns the  name of the entity (class, interface, array class,

     * primitive type, or void) represented by this {@code Class} object,

     * as a {@code String}.

     *

     * <p> If this class object represents a reference type that is not an

     * array type then the binary name of the class is returned, as specified

     * by

     * <cite>The Java&trade; Language Specification</cite>.

     *

     * <p> If this class object represents a primitive type or void, then the

     * name returned is a {@code String} equal to the Java language

     * keyword corresponding to the primitive type or void.

     *

     * <p> If this class object represents a class of arrays, then the internal

     * form of the name consists of the name of the element type preceded by

     * one or more '{@code [}' characters representing the depth of the array

     * nesting.  The encoding of element type names is as follows:

     *

     * <blockquote><table summary="Element types and encodings">

     * <tr><th> Element Type <th> &nbsp;&nbsp;&nbsp; <th> Encoding

     * <tr><td> boolean      <td> &nbsp;&nbsp;&nbsp; <td align=center> Z

     * <tr><td> byte         <td> &nbsp;&nbsp;&nbsp; <td align=center> B

     * <tr><td> char         <td> &nbsp;&nbsp;&nbsp; <td align=center> C

     * <tr><td> class or interface

     *                       <td> &nbsp;&nbsp;&nbsp; <td align=center> L<i>classname</i>;

     * <tr><td> double       <td> &nbsp;&nbsp;&nbsp; <td align=center> D

     * <tr><td> float        <td> &nbsp;&nbsp;&nbsp; <td align=center> F

     * <tr><td> int          <td> &nbsp;&nbsp;&nbsp; <td align=center> I

     * <tr><td> long         <td> &nbsp;&nbsp;&nbsp; <td align=center> J

     * <tr><td> short        <td> &nbsp;&nbsp;&nbsp; <td align=center> S

     * </table></blockquote>

     *

     * <p> The class or interface name <i>classname</i> is the binary name of

     * the class specified above.

     *

     * <p> Examples:

     * <blockquote><pre>

     * String.class.getName()

     *     returns "java.lang.String"

     * byte.class.getName()

     *     returns "byte"

     * (new Object[3]).getClass().getName()

     *     returns "[Ljava.lang.Object;"

     * (new int[3][4][5][6][7][8][9]).getClass().getName()

     *     returns "[[[[[[[I"

     * </pre></blockquote>

     *

     * @return  the name of the class or interface

     *          represented by this object.

     */

    public String getName() {

        String name = this.name;

        if (name == null)

            this.name = name = getName0();

        return name;

    }

    // cache the name to reduce the number of calls into the VM

    private transient String name;

    private native String getName0();

    /**

     * Returns the class loader for the class.  Some implementations may use

     * null to represent the bootstrap class loader. This method will return

     * null in such implementations if this class was loaded by the bootstrap

     * class loader.

     *

     * <p> If a security manager is present, and the caller's class loader is

     * not null and the caller's class loader is not the same as or an ancestor of

     * the class loader for the class whose class loader is requested, then

     * this method calls the security manager's {@code checkPermission}

     * method with a {@code RuntimePermission("getClassLoader")}

     * permission to ensure it's ok to access the class loader for the class.

     *

     * <p>If this object

     * represents a primitive type or void, null is returned.

     *

     * @return  the class loader that loaded the class or interface

     *          represented by this object.

     * @throws SecurityException

     *    if a security manager exists and its

     *    {@code checkPermission} method denies

     *    access to the class loader for the class.

     * @see java.lang.ClassLoader

     * @see SecurityManager#checkPermission

     * @see java.lang.RuntimePermission

     */

    public ClassLoader getClassLoader() {

        ClassLoader cl = getClassLoader0();

        if (cl == null)

            return null;

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            ClassLoader ccl = ClassLoader.getCallerClassLoader();

            if (ccl != null && ccl != cl && !cl.isAncestor(ccl)) {

                sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);

            }

        }

        return cl;

    }

    // Package-private to allow ClassLoader access

    native ClassLoader getClassLoader0();

    /**

     * Returns an array of {@code TypeVariable} objects that represent the

     * type variables declared by the generic declaration represented by this

     * {@code GenericDeclaration} object, in declaration order.  Returns an

     * array of length 0 if the underlying generic declaration declares no type

     * variables.

     *

     * @return an array of {@code TypeVariable} objects that represent

     *     the type variables declared by this generic declaration

     * @throws java.lang.reflect.GenericSignatureFormatError if the generic

     *     signature of this generic declaration does not conform to

     *     the format specified in

     *     <cite>The Java&trade; Virtual Machine Specification</cite>

     * @since 1.5

     */

    public TypeVariable<Class<T>>[] getTypeParameters() {

        if (getGenericSignature() != null)

            return (TypeVariable<Class<T>>[])getGenericInfo().getTypeParameters();

        else

            return (TypeVariable<Class<T>>[])new TypeVariable<?>[0];

    }

    /**

     * Returns the {@code Class} representing the superclass of the entity

     * (class, interface, primitive type or void) represented by this

     * {@code Class}.  If this {@code Class} represents either the

     * {@code Object} class, an interface, a primitive type, or void, then

     * null is returned.  If this object represents an array class then the

     * {@code Class} object representing the {@code Object} class is

     * returned.

     *

     * @return the superclass of the class represented by this object.

     */

    public native Class<? super T> getSuperclass();

    /**

     * Returns the {@code Type} representing the direct superclass of

     * the entity (class, interface, primitive type or void) represented by

     * this {@code Class}.

     *

     * <p>If the superclass is a parameterized type, the {@code Type}

     * object returned must accurately reflect the actual type

     * parameters used in the source code. The parameterized type

     * representing the superclass is created if it had not been

     * created before. See the declaration of {@link

     * java.lang.reflect.ParameterizedType ParameterizedType} for the

     * semantics of the creation process for parameterized types.  If

     * this {@code Class} represents either the {@code Object}

     * class, an interface, a primitive type, or void, then null is

     * returned.  If this object represents an array class then the

     * {@code Class} object representing the {@code Object} class is

     * returned.

     *

     * @throws java.lang.reflect.GenericSignatureFormatError if the generic

     *     class signature does not conform to the format specified in

     *     <cite>The Java&trade; Virtual Machine Specification</cite>

     * @throws TypeNotPresentException if the generic superclass

     *     refers to a non-existent type declaration

     * @throws java.lang.reflect.MalformedParameterizedTypeException if the

     *     generic superclass refers to a parameterized type that cannot be

     *     instantiated  for any reason

     * @return the superclass of the class represented by this object

     * @since 1.5

     */

    public Type getGenericSuperclass() {

        if (getGenericSignature() != null) {

            // Historical irregularity:

            // Generic signature marks interfaces with superclass = Object

            // but this API returns null for interfaces

            if (isInterface())

                return null;

            return getGenericInfo().getSuperclass();

        } else

            return getSuperclass();

    }

    /**

     * Gets the package for this class.  The class loader of this class is used

     * to find the package.  If the class was loaded by the bootstrap class

     * loader the set of packages loaded from CLASSPATH is searched to find the

     * package of the class. Null is returned if no package object was created

     * by the class loader of this class.

     *

     * <p> Packages have attributes for versions and specifications only if the

     * information was defined in the manifests that accompany the classes, and

     * if the class loader created the package instance with the attributes

     * from the manifest.

     *

     * @return the package of the class, or null if no package

     *         information is available from the archive or codebase.

     */

    public Package getPackage() {

        return Package.getPackage(this);

    }

    /**

     * Determines the interfaces implemented by the class or interface

     * represented by this object.

     *

     * <p> If this object represents a class, the return value is an array

     * containing objects representing all interfaces implemented by the

     * class. The order of the interface objects in the array corresponds to

     * the order of the interface names in the {@code implements} clause

     * of the declaration of the class represented by this object. For

     * example, given the declaration:

     * <blockquote>

     * {@code class Shimmer implements FloorWax, DessertTopping { ... }}

     * </blockquote>

     * suppose the value of {@code s} is an instance of

     * {@code Shimmer}; the value of the expression:

     * <blockquote>

     * {@code s.getClass().getInterfaces()[0]}

     * </blockquote>

     * is the {@code Class} object that represents interface

     * {@code FloorWax}; and the value of:

     * <blockquote>

     * {@code s.getClass().getInterfaces()[1]}

     * </blockquote>

     * is the {@code Class} object that represents interface

     * {@code DessertTopping}.

     *

     * <p> If this object represents an interface, the array contains objects

     * representing all interfaces extended by the interface. The order of the

     * interface objects in the array corresponds to the order of the interface

     * names in the {@code extends} clause of the declaration of the

     * interface represented by this object.

     *

     * <p> If this object represents a class or interface that implements no

     * interfaces, the method returns an array of length 0.

     *

     * <p> If this object represents a primitive type or void, the method

     * returns an array of length 0.

     *

     * @return an array of interfaces implemented by this class.

     */

    public native Class<?>[] getInterfaces();

    /**

     * Returns the {@code Type}s representing the interfaces

     * directly implemented by the class or interface represented by

     * this object.

     *

     * <p>If a superinterface is a parameterized type, the

     * {@code Type} object returned for it must accurately reflect

     * the actual type parameters used in the source code. The

     * parameterized type representing each superinterface is created

     * if it had not been created before. See the declaration of

     * {@link java.lang.reflect.ParameterizedType ParameterizedType}

     * for the semantics of the creation process for parameterized

     * types.

     *

     * <p> If this object represents a class, the return value is an

     * array containing objects representing all interfaces

     * implemented by the class. The order of the interface objects in

     * the array corresponds to the order of the interface names in

     * the {@code implements} clause of the declaration of the class

     * represented by this object.  In the case of an array class, the

     * interfaces {@code Cloneable} and {@code Serializable} are

     * returned in that order.

     *

     * <p>If this object represents an interface, the array contains

     * objects representing all interfaces directly extended by the

     * interface.  The order of the interface objects in the array

     * corresponds to the order of the interface names in the

     * {@code extends} clause of the declaration of the interface

     * represented by this object.

     *

     * <p>If this object represents a class or interface that

     * implements no interfaces, the method returns an array of length

     * 0.

     *

     * <p>If this object represents a primitive type or void, the

     * method returns an array of length 0.

     *

     * @throws java.lang.reflect.GenericSignatureFormatError

     *     if the generic class signature does not conform to the format

     *     specified in

     *     <cite>The Java&trade; Virtual Machine Specification</cite>

     * @throws TypeNotPresentException if any of the generic

     *     superinterfaces refers to a non-existent type declaration

     * @throws java.lang.reflect.MalformedParameterizedTypeException

     *     if any of the generic superinterfaces refer to a parameterized

     *     type that cannot be instantiated for any reason

     * @return an array of interfaces implemented by this class

     * @since 1.5

     */

    public Type[] getGenericInterfaces() {

        if (getGenericSignature() != null)

            return getGenericInfo().getSuperInterfaces();

        else

            return getInterfaces();

    }

    /**

     * Returns the {@code Class} representing the component type of an

     * array.  If this class does not represent an array class this method

     * returns null.

     *

     * @return the {@code Class} representing the component type of this

     * class if this class is an array

     * @see     java.lang.reflect.Array

     * @since JDK1.1

     */

    public native Class<?> getComponentType();

    /**

     * Returns the Java language modifiers for this class or interface, encoded

     * in an integer. The modifiers consist of the Java Virtual Machine's

     * constants for {@code public}, {@code protected},

     * {@code private}, {@code final}, {@code static},

     * {@code abstract} and {@code interface}; they should be decoded

     * using the methods of class {@code Modifier}.

     *

     * <p> If the underlying class is an array class, then its

     * {@code public}, {@code private} and {@code protected}

     * modifiers are the same as those of its component type.  If this

     * {@code Class} represents a primitive type or void, its

     * {@code public} modifier is always {@code true}, and its

     * {@code protected} and {@code private} modifiers are always

     * {@code false}. If this object represents an array class, a

     * primitive type or void, then its {@code final} modifier is always

     * {@code true} and its interface modifier is always

     * {@code false}. The values of its other modifiers are not determined

     * by this specification.

     *

     * <p> The modifier encodings are defined in <em>The Java Virtual Machine

     * Specification</em>, table 4.1.

     *

     * @return the {@code int} representing the modifiers for this class

     * @see     java.lang.reflect.Modifier

     * @since JDK1.1

     */

    public native int getModifiers();

    /**

     * Gets the signers of this class.

     *

     * @return  the signers of this class, or null if there are no signers.  In

     *          particular, this method returns null if this object represents

     *          a primitive type or void.

     * @since   JDK1.1

     */

    public native Object[] getSigners();

    /**

     * Set the signers of this class.

     */

    native void setSigners(Object[] signers);

    /**

     * If this {@code Class} object represents a local or anonymous

     * class within a method, returns a {@link

     * java.lang.reflect.Method Method} object representing the

     * immediately enclosing method of the underlying class. Returns

     * {@code null} otherwise.

     *

     * In particular, this method returns {@code null} if the underlying

     * class is a local or anonymous class immediately enclosed by a type

     * declaration, instance initializer or static initializer.

     *

     * @return the immediately enclosing method of the underlying class, if

     *     that class is a local or anonymous class; otherwise {@code null}.

     * @since 1.5

     */

    public Method getEnclosingMethod() {

        EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();

        if (enclosingInfo == null)

            return null;

        else {

            if (!enclosingInfo.isMethod())

                return null;

            MethodRepository typeInfo = MethodRepository.make(enclosingInfo.getDescriptor(),

                                                              getFactory());

            Class<?>   returnType       = toClass(typeInfo.getReturnType());

            Type []    parameterTypes   = typeInfo.getParameterTypes();

            Class<?>[] parameterClasses = new Class<?>[parameterTypes.length];

            // Convert Types to Classes; returned types *should*

            // be class objects since the methodDescriptor's used

            // don't have generics information

            for(int i = 0; i < parameterClasses.length; i++)

                parameterClasses[i] = toClass(parameterTypes[i]);

            /*

             * Loop over all declared methods; match method name,

             * number of and type of parameters, *and* return

             * type.  Matching return type is also necessary

             * because of covariant returns, etc.

             */

            for(Method m: enclosingInfo.getEnclosingClass().getDeclaredMethods()) {

                if (m.getName().equals(enclosingInfo.getName()) ) {

                    Class<?>[] candidateParamClasses = m.getParameterTypes();

                    if (candidateParamClasses.length == parameterClasses.length) {

                        boolean matches = true;

                        for(int i = 0; i < candidateParamClasses.length; i++) {

                            if (!candidateParamClasses[i].equals(parameterClasses[i])) {

                                matches = false;

                                break;

                            }

                        }

                        if (matches) { // finally, check return type

                            if (m.getReturnType().equals(returnType) )

                                return m;

                        }

                    }

                }

            }

            throw new InternalError("Enclosing method not found");

        }

    }

    private native Object[] getEnclosingMethod0();

    private EnclosingMethodInfo getEnclosingMethodInfo() {

        Object[] enclosingInfo = getEnclosingMethod0();

        if (enclosingInfo == null)

            return null;

        else {

            return new EnclosingMethodInfo(enclosingInfo);

        }

    }

    private final static class EnclosingMethodInfo {

        private Class<?> enclosingClass;

        private String name;

        private String descriptor;

        private EnclosingMethodInfo(Object[] enclosingInfo) {

            if (enclosingInfo.length != 3)

                throw new InternalError("Malformed enclosing method information");

            try {

                // The array is expected to have three elements:

                // the immediately enclosing class

                enclosingClass = (Class<?>) enclosingInfo[0];

                assert(enclosingClass != null);

                // the immediately enclosing method or constructor's

                // name (can be null).

                name            = (String)   enclosingInfo[1];

                // the immediately enclosing method or constructor's

                // descriptor (null iff name is).

                descriptor      = (String)   enclosingInfo[2];

                assert((name != null && descriptor != null) || name == descriptor);

            } catch (ClassCastException cce) {

                throw new InternalError("Invalid type in enclosing method information");

            }

        }

        boolean isPartial() {

            return enclosingClass == null || name == null || descriptor == null;

        }

        boolean isConstructor() { return !isPartial() && "<init>".equals(name); }

        boolean isMethod() { return !isPartial() && !isConstructor() && !"<clinit>".equals(name); }

        Class<?> getEnclosingClass() { return enclosingClass; }