/*

 * Copyright (c) 1994, 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.

 */

package java.lang;

import  java.io.*;

import org.apidesign.bck2brwsr.core.JavaScriptBody;

/**

 * The {@code Throwable} class is the superclass of all errors and

 * exceptions in the Java language. Only objects that are instances of this

 * class (or one of its subclasses) are thrown by the Java Virtual Machine or

 * can be thrown by the Java {@code throw} statement. Similarly, only

 * this class or one of its subclasses can be the argument type in a

 * {@code catch} clause.

 *

 * For the purposes of compile-time checking of exceptions, {@code

 * Throwable} and any subclass of {@code Throwable} that is not also a

 * subclass of either {@link RuntimeException} or {@link Error} are

 * regarded as checked exceptions.

 *

 * <p>Instances of two subclasses, {@link java.lang.Error} and

 * {@link java.lang.Exception}, are conventionally used to indicate

 * that exceptional situations have occurred. Typically, these instances

 * are freshly created in the context of the exceptional situation so

 * as to include relevant information (such as stack trace data).

 *

 * <p>A throwable contains a snapshot of the execution stack of its

 * thread at the time it was created. It can also contain a message

 * string that gives more information about the error. Over time, a

 * throwable can {@linkplain Throwable#addSuppressed suppress} other

 * throwables from being propagated.  Finally, the throwable can also

 * contain a <i>cause</i>: another throwable that caused this

 * throwable to be constructed.  The recording of this causal information

 * is referred to as the <i>chained exception</i> facility, as the

 * cause can, itself, have a cause, and so on, leading to a "chain" of

 * exceptions, each caused by another.

 *

 * <p>One reason that a throwable may have a cause is that the class that

 * throws it is built atop a lower layered abstraction, and an operation on

 * the upper layer fails due to a failure in the lower layer.  It would be bad

 * design to let the throwable thrown by the lower layer propagate outward, as

 * it is generally unrelated to the abstraction provided by the upper layer.

 * Further, doing so would tie the API of the upper layer to the details of

 * its implementation, assuming the lower layer's exception was a checked

 * exception.  Throwing a "wrapped exception" (i.e., an exception containing a

 * cause) allows the upper layer to communicate the details of the failure to

 * its caller without incurring either of these shortcomings.  It preserves

 * the flexibility to change the implementation of the upper layer without

 * changing its API (in particular, the set of exceptions thrown by its

 * methods).

 *

 * <p>A second reason that a throwable may have a cause is that the method

 * that throws it must conform to a general-purpose interface that does not

 * permit the method to throw the cause directly.  For example, suppose

 * a persistent collection conforms to the {@link java.util.Collection

 * Collection} interface, and that its persistence is implemented atop

 * {@code java.io}.  Suppose the internals of the {@code add} method

 * can throw an {@link java.io.IOException IOException}.  The implementation

 * can communicate the details of the {@code IOException} to its caller

 * while conforming to the {@code Collection} interface by wrapping the

 * {@code IOException} in an appropriate unchecked exception.  (The

 * specification for the persistent collection should indicate that it is

 * capable of throwing such exceptions.)

 *

 * <p>A cause can be associated with a throwable in two ways: via a

 * constructor that takes the cause as an argument, or via the

 * {@link #initCause(Throwable)} method.  New throwable classes that

 * wish to allow causes to be associated with them should provide constructors

 * that take a cause and delegate (perhaps indirectly) to one of the

 * {@code Throwable} constructors that takes a cause.

 *

 * Because the {@code initCause} method is public, it allows a cause to be

 * associated with any throwable, even a "legacy throwable" whose

 * implementation predates the addition of the exception chaining mechanism to

 * {@code Throwable}.

 *

 * <p>By convention, class {@code Throwable} and its subclasses have two

 * constructors, one that takes no arguments and one that takes a

 * {@code String} argument that can be used to produce a detail message.

 * Further, those subclasses that might likely have a cause associated with

 * them should have two more constructors, one that takes a

 * {@code Throwable} (the cause), and one that takes a

 * {@code String} (the detail message) and a {@code Throwable} (the

 * cause).

 *

 * @author  unascribed

 * @author  Josh Bloch (Added exception chaining and programmatic access to

 *          stack trace in 1.4.)

 * @jls 11.2 Compile-Time Checking of Exceptions

 * @since JDK1.0

 */

public class Throwable implements Serializable {

    /** use serialVersionUID from JDK 1.0.2 for interoperability */

    private static final long serialVersionUID = -3042686055658047285L;

    /**

     * Native code saves some indication of the stack backtrace in this slot.

     */

    private transient Object backtrace;

    /**

     * Specific details about the Throwable.  For example, for

     * {@code FileNotFoundException}, this contains the name of

     * the file that could not be found.

     *

     * @serial

     */

    private String detailMessage;

    /**

     * Holder class to defer initializing sentinel objects only used

     * for serialization.

     */

    private static class SentinelHolder {

        /**

         * {@linkplain #setStackTrace(StackTraceElement[]) Setting the

         * stack trace} to a one-element array containing this sentinel

         * value indicates future attempts to set the stack trace will be

         * ignored.  The sentinal is equal to the result of calling:<br>

         * {@code new StackTraceElement("", "", null, Integer.MIN_VALUE)}

         */

        public static final StackTraceElement STACK_TRACE_ELEMENT_SENTINEL =

            new StackTraceElement("", "", null, Integer.MIN_VALUE);

        /**

         * Sentinel value used in the serial form to indicate an immutable

         * stack trace.

         */

        public static final StackTraceElement[] STACK_TRACE_SENTINEL =

            new StackTraceElement[] {STACK_TRACE_ELEMENT_SENTINEL};

    }

    /**

     * A shared value for an empty stack.

     */

    private static final StackTraceElement[] UNASSIGNED_STACK = new StackTraceElement[0];

    /*

     * To allow Throwable objects to be made immutable and safely

     * reused by the JVM, such as OutOfMemoryErrors, fields of

     * Throwable that are writable in response to user actions, cause,

     * stackTrace, and suppressedExceptions obey the following

     * protocol:

     *

     * 1) The fields are initialized to a non-null sentinel value

     * which indicates the value has logically not been set.

     *

     * 2) Writing a null to the field indicates further writes

     * are forbidden

     *

     * 3) The sentinel value may be replaced with another non-null

     * value.

     *

     * For example, implementations of the HotSpot JVM have

     * preallocated OutOfMemoryError objects to provide for better

     * diagnosability of that situation.  These objects are created

     * without calling the constructor for that class and the fields

     * in question are initialized to null.  To support this

     * capability, any new fields added to Throwable that require

     * being initialized to a non-null value require a coordinated JVM

     * change.

     */

    /**

     * The throwable that caused this throwable to get thrown, or null if this

     * throwable was not caused by another throwable, or if the causative

     * throwable is unknown.  If this field is equal to this throwable itself,

     * it indicates that the cause of this throwable has not yet been

     * initialized.

     *

     * @serial

     * @since 1.4

     */

    private Throwable cause = this;

    /**

     * The stack trace, as returned by {@link #getStackTrace()}.

     *

     * The field is initialized to a zero-length array.  A {@code

     * null} value of this field indicates subsequent calls to {@link

     * #setStackTrace(StackTraceElement[])} and {@link

     * #fillInStackTrace()} will be be no-ops.

     *

     * @serial

     * @since 1.4

     */

    private StackTraceElement[] stackTrace = UNASSIGNED_STACK;

    // Setting this static field introduces an acceptable

    // initialization dependency on a few java.util classes.

// I don't think this dependency is acceptable

//    private static final List<Throwable> SUPPRESSED_SENTINEL =

//        Collections.unmodifiableList(new ArrayList<Throwable>(0));

    /**

     * The list of suppressed exceptions, as returned by {@link

     * #getSuppressed()}.  The list is initialized to a zero-element

     * unmodifiable sentinel list.  When a serialized Throwable is

     * read in, if the {@code suppressedExceptions} field points to a

     * zero-element list, the field is reset to the sentinel value.

     *

     * @serial

     * @since 1.7

     */

//    private List<Throwable> suppressedExceptions = SUPPRESSED_SENTINEL;

    /** Message for trying to suppress a null exception. */

    private static final String NULL_CAUSE_MESSAGE = "Cannot suppress a null exception.";

    /** Message for trying to suppress oneself. */

    private static final String SELF_SUPPRESSION_MESSAGE = "Self-suppression not permitted";

    /** Caption  for labeling causative exception stack traces */

    private static final String CAUSE_CAPTION = "Caused by: ";

    /** Caption for labeling suppressed exception stack traces */

    private static final String SUPPRESSED_CAPTION = "Suppressed: ";

    /**

     * Constructs a new throwable with {@code null} as its detail message.

     * The cause is not initialized, and may subsequently be initialized by a

     * call to {@link #initCause}.

     *

     * <p>The {@link #fillInStackTrace()} method is called to initialize

     * the stack trace data in the newly created throwable.

     */

    public Throwable() {

        fillInStackTrace();

    }

    /**

     * Constructs a new throwable with the specified detail message.  The

     * cause is not initialized, and may subsequently be initialized by

     * a call to {@link #initCause}.

     *

     * <p>The {@link #fillInStackTrace()} method is called to initialize

     * the stack trace data in the newly created throwable.

     *

     * @param   message   the detail message. The detail message is saved for

     *          later retrieval by the {@link #getMessage()} method.

     */

    public Throwable(String message) {

        fillInStackTrace();

        detailMessage = message;

    }

    /**

     * Constructs a new throwable with the specified detail message and

     * cause.  <p>Note that the detail message associated with

     * {@code cause} is <i>not</i> automatically incorporated in

     * this throwable's detail message.

     *

     * <p>The {@link #fillInStackTrace()} method is called to initialize

     * the stack trace data in the newly created throwable.

     *

     * @param  message the detail message (which is saved for later retrieval

     *         by the {@link #getMessage()} method).

     * @param  cause the cause (which is saved for later retrieval by the

     *         {@link #getCause()} method).  (A {@code null} value is

     *         permitted, and indicates that the cause is nonexistent or

     *         unknown.)

     * @since  1.4

     */

    public Throwable(String message, Throwable cause) {

        fillInStackTrace();

        detailMessage = message;

        this.cause = cause;

    }

    /**

     * Constructs a new throwable with the specified cause and a detail

     * message of {@code (cause==null ? null : cause.toString())} (which

     * typically contains the class and detail message of {@code cause}).

     * This constructor is useful for throwables that are little more than

     * wrappers for other throwables (for example, {@link

     * java.security.PrivilegedActionException}).

     *

     * <p>The {@link #fillInStackTrace()} method is called to initialize

     * the stack trace data in the newly created throwable.

     *

     * @param  cause the cause (which is saved for later retrieval by the

     *         {@link #getCause()} method).  (A {@code null} value is

     *         permitted, and indicates that the cause is nonexistent or

     *         unknown.)

     * @since  1.4

     */

    public Throwable(Throwable cause) {

        fillInStackTrace();

        detailMessage = (cause==null ? null : cause.toString());

        this.cause = cause;

    }

    /**

     * Constructs a new throwable with the specified detail message,

     * cause, {@linkplain #addSuppressed suppression} enabled or

     * disabled, and writable stack trace enabled or disabled.  If

     * suppression is disabled, {@link #getSuppressed} for this object

     * will return a zero-length array and calls to {@link

     * #addSuppressed} that would otherwise append an exception to the

     * suppressed list will have no effect.  If the writable stack

     * trace is false, this constructor will not call {@link

     * #fillInStackTrace()}, a {@code null} will be written to the

     * {@code stackTrace} field, and subsequent calls to {@code

     * fillInStackTrace} and {@link

     * #setStackTrace(StackTraceElement[])} will not set the stack

     * trace.  If the writable stack trace is false, {@link

     * #getStackTrace} will return a zero length array.

     *

     * <p>Note that the other constructors of {@code Throwable} treat

     * suppression as being enabled and the stack trace as being

     * writable.  Subclasses of {@code Throwable} should document any

     * conditions under which suppression is disabled and document

     * conditions under which the stack trace is not writable.

     * Disabling of suppression should only occur in exceptional

     * circumstances where special requirements exist, such as a

     * virtual machine reusing exception objects under low-memory

     * situations.  Circumstances where a given exception object is

     * repeatedly caught and rethrown, such as to implement control

     * flow between two sub-systems, is another situation where

     * immutable throwable objects would be appropriate.

     *

     * @param  message the detail message.

     * @param cause the cause.  (A {@code null} value is permitted,

     * and indicates that the cause is nonexistent or unknown.)

     * @param enableSuppression whether or not suppression is enabled or disabled

     * @param writableStackTrace whether or not the stack trace should be

     *                           writable

     *

     * @see OutOfMemoryError

     * @see NullPointerException

     * @see ArithmeticException

     * @since 1.7

     */

    protected Throwable(String message, Throwable cause,

                        boolean enableSuppression,

                        boolean writableStackTrace) {

        if (writableStackTrace) {

            fillInStackTrace();

        } else {

            stackTrace = null;

        }

        detailMessage = message;

        this.cause = cause;

//        if (!enableSuppression)

//            suppressedExceptions = null;

    }

    /**

     * Returns the detail message string of this throwable.

     *

     * @return  the detail message string of this {@code Throwable} instance

     *          (which may be {@code null}).

     */

    public String getMessage() {

        return detailMessage;

    }

    /**

     * Creates a localized description of this throwable.

     * Subclasses may override this method in order to produce a

     * locale-specific message.  For subclasses that do not override this

     * method, the default implementation returns the same result as

     * {@code getMessage()}.

     *

     * @return  The localized description of this throwable.

     * @since   JDK1.1

     */

    public String getLocalizedMessage() {

        return getMessage();

    }

    /**

     * Returns the cause of this throwable or {@code null} if the

     * cause is nonexistent or unknown.  (The cause is the throwable that

     * caused this throwable to get thrown.)

     *

     * <p>This implementation returns the cause that was supplied via one of

     * the constructors requiring a {@code Throwable}, or that was set after

     * creation with the {@link #initCause(Throwable)} method.  While it is

     * typically unnecessary to override this method, a subclass can override

     * it to return a cause set by some other means.  This is appropriate for

     * a "legacy chained throwable" that predates the addition of chained

     * exceptions to {@code Throwable}.  Note that it is <i>not</i>

     * necessary to override any of the {@code PrintStackTrace} methods,

     * all of which invoke the {@code getCause} method to determine the

     * cause of a throwable.

     *

     * @return  the cause of this throwable or {@code null} if the

     *          cause is nonexistent or unknown.

     * @since 1.4

     */

    public synchronized Throwable getCause() {

        return (cause==this ? null : cause);

    }

    /**

     * Initializes the <i>cause</i> of this throwable to the specified value.

     * (The cause is the throwable that caused this throwable to get thrown.)

     *

     * <p>This method can be called at most once.  It is generally called from

     * within the constructor, or immediately after creating the

     * throwable.  If this throwable was created

     * with {@link #Throwable(Throwable)} or

     * {@link #Throwable(String,Throwable)}, this method cannot be called

     * even once.

     *

     * <p>An example of using this method on a legacy throwable type

     * without other support for setting the cause is:

     *

     * <pre>

     * try {

     *     lowLevelOp();

     * } catch (LowLevelException le) {

     *     throw (HighLevelException)

     *           new HighLevelException().initCause(le); // Legacy constructor

     * }

     * </pre>

     *

     * @param  cause the cause (which is saved for later retrieval by the

     *         {@link #getCause()} method).  (A {@code null} value is

     *         permitted, and indicates that the cause is nonexistent or

     *         unknown.)

     * @return  a reference to this {@code Throwable} instance.

     * @throws IllegalArgumentException if {@code cause} is this

     *         throwable.  (A throwable cannot be its own cause.)

     * @throws IllegalStateException if this throwable was

     *         created with {@link #Throwable(Throwable)} or

     *         {@link #Throwable(String,Throwable)}, or this method has already

     *         been called on this throwable.

     * @since  1.4

     */

    public synchronized Throwable initCause(Throwable cause) {

        if (this.cause != this)

            throw new IllegalStateException("Can't overwrite cause");

        if (cause == this)

            throw new IllegalArgumentException("Self-causation not permitted");

        this.cause = cause;

        return this;

    }

    /**

     * Returns a short description of this throwable.

     * The result is the concatenation of:

     * <ul>

     * <li> the {@linkplain Class#getName() name} of the class of this object

     * <li> ": " (a colon and a space)

     * <li> the result of invoking this object's {@link #getLocalizedMessage}

     *      method

     * </ul>

     * If {@code getLocalizedMessage} returns {@code null}, then just

     * the class name is returned.

     *

     * @return a string representation of this throwable.

     */

    public String toString() {

        String s = getClass().getName();

        String message = getLocalizedMessage();

        return (message != null) ? (s + ": " + message) : s;

    }

    /**

     * Prints this throwable and its backtrace to the

     * standard error stream. This method prints a stack trace for this

     * {@code Throwable} object on the error output stream that is

     * the value of the field {@code System.err}. The first line of

     * output contains the result of the {@link #toString()} method for

     * this object.  Remaining lines represent data previously recorded by

     * the method {@link #fillInStackTrace()}. The format of this

     * information depends on the implementation, but the following

     * example may be regarded as typical:

     * <blockquote><pre>

     * java.lang.NullPointerException

     *         at MyClass.mash(MyClass.java:9)

     *         at MyClass.crunch(MyClass.java:6)

     *         at MyClass.main(MyClass.java:3)

     * </pre></blockquote>

     * This example was produced by running the program:

     * <pre>

     * class MyClass {

     *     public static void main(String[] args) {

     *         crunch(null);

     *     }

     *     static void crunch(int[] a) {

     *         mash(a);

     *     }

     *     static void mash(int[] b) {

     *         System.out.println(b[0]);

     *     }

     * }

     * </pre>

     * The backtrace for a throwable with an initialized, non-null cause

     * should generally include the backtrace for the cause.  The format

     * of this information depends on the implementation, but the following

     * example may be regarded as typical:

     * <pre>

     * HighLevelException: MidLevelException: LowLevelException

     *         at Junk.a(Junk.java:13)

     *         at Junk.main(Junk.java:4)

     * Caused by: MidLevelException: LowLevelException

     *         at Junk.c(Junk.java:23)

     *         at Junk.b(Junk.java:17)

     *         at Junk.a(Junk.java:11)

     *         ... 1 more

     * Caused by: LowLevelException

     *         at Junk.e(Junk.java:30)

     *         at Junk.d(Junk.java:27)

     *         at Junk.c(Junk.java:21)

     *         ... 3 more

     * </pre>

     * Note the presence of lines containing the characters {@code "..."}.

     * These lines indicate that the remainder of the stack trace for this

     * exception matches the indicated number of frames from the bottom of the

     * stack trace of the exception that was caused by this exception (the

     * "enclosing" exception).  This shorthand can greatly reduce the length

     * of the output in the common case where a wrapped exception is thrown

     * from same method as the "causative exception" is caught.  The above

     * example was produced by running the program:

     * <pre>

     * public class Junk {

     *     public static void main(String args[]) {

     *         try {

     *             a();

     *         } catch(HighLevelException e) {

     *             e.printStackTrace();

     *         }

     *     }

     *     static void a() throws HighLevelException {

     *         try {

     *             b();

     *         } catch(MidLevelException e) {

     *             throw new HighLevelException(e);

     *         }

     *     }

     *     static void b() throws MidLevelException {

     *         c();

     *     }

     *     static void c() throws MidLevelException {

     *         try {

     *             d();

     *         } catch(LowLevelException e) {

     *             throw new MidLevelException(e);

     *         }

     *     }

     *     static void d() throws LowLevelException {

     *        e();

     *     }

     *     static void e() throws LowLevelException {

     *         throw new LowLevelException();

     *     }

     * }

     *

     * class HighLevelException extends Exception {

     *     HighLevelException(Throwable cause) { super(cause); }

     * }

     *

     * class MidLevelException extends Exception {

     *     MidLevelException(Throwable cause)  { super(cause); }

     * }

     *

     * class LowLevelException extends Exception {

     * }

     * </pre>

     * As of release 7, the platform supports the notion of

     * <i>suppressed exceptions</i> (in conjunction with the {@code

     * try}-with-resources statement). Any exceptions that were

     * suppressed in order to deliver an exception are printed out

     * beneath the stack trace.  The format of this information

     * depends on the implementation, but the following example may be

     * regarded as typical:

     *

     * <pre>

     * Exception in thread "main" java.lang.Exception: Something happened

     *  at Foo.bar(Foo.java:10)

     *  at Foo.main(Foo.java:5)

     *  Suppressed: Resource$CloseFailException: Resource ID = 0

     *          at Resource.close(Resource.java:26)

     *          at Foo.bar(Foo.java:9)

     *          ... 1 more

     * </pre>

     * Note that the "... n more" notation is used on suppressed exceptions

     * just at it is used on causes. Unlike causes, suppressed exceptions are

     * indented beyond their "containing exceptions."

     *

     * <p>An exception can have both a cause and one or more suppressed

     * exceptions:

     * <pre>

     * Exception in thread "main" java.lang.Exception: Main block

     *  at Foo3.main(Foo3.java:7)

     *  Suppressed: Resource$CloseFailException: Resource ID = 2

     *          at Resource.close(Resource.java:26)

     *          at Foo3.main(Foo3.java:5)

     *  Suppressed: Resource$CloseFailException: Resource ID = 1

     *          at Resource.close(Resource.java:26)

     *          at Foo3.main(Foo3.java:5)

     * Caused by: java.lang.Exception: I did it

     *  at Foo3.main(Foo3.java:8)

     * </pre>

     * Likewise, a suppressed exception can have a cause:

     * <pre>

     * Exception in thread "main" java.lang.Exception: Main block

     *  at Foo4.main(Foo4.java:6)

     *  Suppressed: Resource2$CloseFailException: Resource ID = 1

     *          at Resource2.close(Resource2.java:20)

     *          at Foo4.main(Foo4.java:5)

     *  Caused by: java.lang.Exception: Rats, you caught me

     *          at Resource2$CloseFailException.<init>(Resource2.java:45)

     *          ... 2 more

     * </pre>

     */

//    public void printStackTrace() {

//        printStackTrace(System.err);

//    }

//

//    /**

//     * Prints this throwable and its backtrace to the specified print stream.

//     *

//     * @param s {@code PrintStream} to use for output

//     */

//    public void printStackTrace(PrintStream s) {

//        printStackTrace(new WrappedPrintStream(s));

//    }

//

//    private void printStackTrace(PrintStreamOrWriter s) {

//        // Guard against malicious overrides of Throwable.equals by

//        // using a Set with identity equality semantics.

////        Set<Throwable> dejaVu =

////            Collections.newSetFromMap(new IdentityHashMap<Throwable, Boolean>());

////        dejaVu.add(this);

//

//        synchronized (s.lock()) {

//            // Print our stack trace

//            s.println(this);

//            StackTraceElement[] trace = getOurStackTrace();

//            for (StackTraceElement traceElement : trace)

//                s.println("\tat " + traceElement);

//

//            // Print suppressed exceptions, if any

////            for (Throwable se : getSuppressed())

////                se.printEnclosedStackTrace(s, trace, SUPPRESSED_CAPTION, "\t", dejaVu);

//

//            // Print cause, if any

//            Throwable ourCause = getCause();

////            if (ourCause != null)

////                ourCause.printEnclosedStackTrace(s, trace, CAUSE_CAPTION, "", dejaVu);

//        }

//    }

//

//    /**

//     * Print our stack trace as an enclosed exception for the specified

//     * stack trace.

//     */

//    private void printEnclosedStackTrace(PrintStreamOrWriter s,

//                                         StackTraceElement[] enclosingTrace,

//                                         String caption,

//                                         String prefix,

//                                         Object dejaVu) {

//        assert Thread.holdsLock(s.lock());

//        {

//            // Compute number of frames in common between this and enclosing trace

//            StackTraceElement[] trace = getOurStackTrace();

//            int m = trace.length - 1;

//            int n = enclosingTrace.length - 1;

//            while (m >= 0 && n >=0 && trace[m].equals(enclosingTrace[n])) {

//                m--; n--;

//            }

//            int framesInCommon = trace.length - 1 - m;

//

//            // Print our stack trace

//            s.println(prefix + caption + this);

//            for (int i = 0; i <= m; i++)

//                s.println(prefix + "\tat " + trace[i]);

//            if (framesInCommon != 0)

//                s.println(prefix + "\t... " + framesInCommon + " more");

//

//            // Print suppressed exceptions, if any

//            for (Throwable se : getSuppressed())

//                se.printEnclosedStackTrace(s, trace, SUPPRESSED_CAPTION,

//                                           prefix +"\t", dejaVu);

//

//            // Print cause, if any

//            Throwable ourCause = getCause();

//            if (ourCause != null)

//                ourCause.printEnclosedStackTrace(s, trace, CAUSE_CAPTION, prefix, dejaVu);

//        }

//    }

//

//    /**

//     * Prints this throwable and its backtrace to the specified

//     * print writer.

//     *

//     * @param s {@code PrintWriter} to use for output

//     * @since   JDK1.1

//     */

//    public void printStackTrace(PrintWriter s) {

//        printStackTrace(new WrappedPrintWriter(s));

//    }

//

//    /**

//     * Wrapper class for PrintStream and PrintWriter to enable a single

//     * implementation of printStackTrace.

//     */

//    private abstract static class PrintStreamOrWriter {

//        /** Returns the object to be locked when using this StreamOrWriter */

//        abstract Object lock();

//

//        /** Prints the specified string as a line on this StreamOrWriter */

//        abstract void println(Object o);

//    }

//

//    private static class WrappedPrintStream extends PrintStreamOrWriter {

//        private final PrintStream printStream;

//

//        WrappedPrintStream(PrintStream printStream) {

//            this.printStream = printStream;

//        }

//

//        Object lock() {

//            return printStream;

//        }

//

//        void println(Object o) {

//            printStream.println(o);

//        }

//    }

//

//    private static class WrappedPrintWriter extends PrintStreamOrWriter {

//        private final PrintWriter printWriter;

//

//        WrappedPrintWriter(PrintWriter printWriter) {

//            this.printWriter = printWriter;

//        }

//

//        Object lock() {

//            return printWriter;

//        }

//

//        void println(Object o) {

//            printWriter.println(o);

//        }

//    }

    /**

     * Fills in the execution stack trace. This method records within this

     * {@code Throwable} object information about the current state of

     * the stack frames for the current thread.

     *

     * <p>If the stack trace of this {@code Throwable} {@linkplain

     * Throwable#Throwable(String, Throwable, boolean, boolean) is not

     * writable}, calling this method has no effect.

     *

     * @return  a reference to this {@code Throwable} instance.

     * @see     java.lang.Throwable#printStackTrace()

     */

    public synchronized Throwable fillInStackTrace() {

        if (stackTrace != null ||

            backtrace != null /* Out of protocol state */ ) {

            fillInStackTrace(0);

            stackTrace = UNASSIGNED_STACK;

        }

        return this;

    }

    @JavaScriptBody(args = { "dummy" }, body = "")

    private native Throwable fillInStackTrace(int dummy);

    /**

     * Provides programmatic access to the stack trace information printed by

     * {@link #printStackTrace()}.  Returns an array of stack trace elements,

     * each representing one stack frame.  The zeroth element of the array

     * (assuming the array's length is non-zero) represents the top of the

     * stack, which is the last method invocation in the sequence.  Typically,

     * this is the point at which this throwable was created and thrown.

     * The last element of the array (assuming the array's length is non-zero)

     * represents the bottom of the stack, which is the first method invocation

     * in the sequence.

     *

     * <p>Some virtual machines may, under some circumstances, omit one

     * or more stack frames from the stack trace.  In the extreme case,

     * a virtual machine that has no stack trace information concerning

     * this throwable is permitted to return a zero-length array from this

     * method.  Generally speaking, the array returned by this method will

     * contain one element for every frame that would be printed by

     * {@code printStackTrace}.  Writes to the returned array do not

     * affect future calls to this method.

     *

     * @return an array of stack trace elements representing the stack trace

     *         pertaining to this throwable.

     * @since  1.4

     */

    public StackTraceElement[] getStackTrace() {

        return getOurStackTrace().clone();

    }

    private synchronized StackTraceElement[] getOurStackTrace() {

        // Initialize stack trace field with information from

        // backtrace if this is the first call to this method

        if (stackTrace == UNASSIGNED_STACK ||

            (stackTrace == null && backtrace != null) /* Out of protocol state */) {

            int depth = getStackTraceDepth();

            stackTrace = new StackTraceElement[depth];

            for (int i=0; i < depth; i++)

                stackTrace[i] = getStackTraceElement(i);

        } else if (stackTrace == null) {

            return UNASSIGNED_STACK;

        }

        return stackTrace;

    }

    /**

     * Sets the stack trace elements that will be returned by

     * {@link #getStackTrace()} and printed by {@link #printStackTrace()}

     * and related methods.

     *

     * This method, which is designed for use by RPC frameworks and other

     * advanced systems, allows the client to override the default

     * stack trace that is either generated by {@link #fillInStackTrace()}

     * when a throwable is constructed or deserialized when a throwable is

     * read from a serialization stream.

     *

     * <p>If the stack trace of this {@code Throwable} {@linkplain

     * Throwable#Throwable(String, Throwable, boolean, boolean) is not

     * writable}, calling this method has no effect other than

     * validating its argument.

     *

     * @param   stackTrace the stack trace elements to be associated with

     * this {@code Throwable}.  The specified array is copied by this

     * call; changes in the specified array after the method invocation

     * returns will have no affect on this {@code Throwable}'s stack

     * trace.

     *

     * @throws NullPointerException if {@code stackTrace} is

     *         {@code null} or if any of the elements of

     *         {@code stackTrace} are {@code null}

     *

     * @since  1.4

     */

    public void setStackTrace(StackTraceElement[] stackTrace) {

        // Validate argument

        StackTraceElement[] defensiveCopy = stackTrace.clone();

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

            if (defensiveCopy[i] == null)

                throw new NullPointerException("stackTrace[" + i + "]");

        }

        synchronized (this) {

            if (this.stackTrace == null && // Immutable stack

                backtrace == null) // Test for out of protocol state

                return;

            this.stackTrace = defensiveCopy;

        }

    }

    /**

     * Returns the number of elements in the stack trace (or 0 if the stack

     * trace is unavailable).

     *

     * package-protection for use by SharedSecrets.

     */

    native int getStackTraceDepth();

    /**

     * Returns the specified element of the stack trace.

     *

     * package-protection for use by SharedSecrets.

     *

     * @param index index of the element to return.

     * @throws IndexOutOfBoundsException if {@code index < 0 ||

     *         index >= getStackTraceDepth() }

     */

    native StackTraceElement getStackTraceElement(int index);

    /**

     * Reads a {@code Throwable} from a stream, enforcing

     * well-formedness constraints on fields.  Null entries and

     * self-pointers are not allowed in the list of {@code

     * suppressedExceptions}.  Null entries are not allowed for stack

     * trace elements.  A null stack trace in the serial form results

     * in a zero-length stack element array. A single-element stack

     * trace whose entry is equal to {@code new StackTraceElement("",

     * "", null, Integer.MIN_VALUE)} results in a {@code null} {@code

     * stackTrace} field.

     *

     * Note that there are no constraints on the value the {@code

     * cause} field can hold; both {@code null} and {@code this} are

     * valid values for the field.

     */

//    private void readObject(ObjectInputStream s)

//        throws IOException, ClassNotFoundException {

//        s.defaultReadObject();     // read in all fields

//        if (suppressedExceptions != null) {

//            List<Throwable> suppressed = null;

//            if (suppressedExceptions.isEmpty()) {

//                // Use the sentinel for a zero-length list

//                suppressed = SUPPRESSED_SENTINEL;

//            } else { // Copy Throwables to new list

//                suppressed = new ArrayList<Throwable>(1);

//                for (Throwable t : suppressedExceptions) {

//                    // Enforce constraints on suppressed exceptions in

//                    // case of corrupt or malicious stream.

//                    if (t == null)

//                        throw new NullPointerException(NULL_CAUSE_MESSAGE);

//                    if (t == this)

//                        throw new IllegalArgumentException(SELF_SUPPRESSION_MESSAGE);

//                    suppressed.add(t);

//                }

//            }

//            suppressedExceptions = suppressed;

//        } // else a null suppressedExceptions field remains null

//

//        /*

//         * For zero-length stack traces, use a clone of

//         * UNASSIGNED_STACK rather than UNASSIGNED_STACK itself to

//         * allow identity comparison against UNASSIGNED_STACK in

//         * getOurStackTrace.  The identity of UNASSIGNED_STACK in

//         * stackTrace indicates to the getOurStackTrace method that

//         * the stackTrace needs to be constructed from the information

//         * in backtrace.

//         */

//        if (stackTrace != null) {

//            if (stackTrace.length == 0) {

//                stackTrace = UNASSIGNED_STACK.clone();

//            }  else if (stackTrace.length == 1 &&

//                        // Check for the marker of an immutable stack trace

//                        SentinelHolder.STACK_TRACE_ELEMENT_SENTINEL.equals(stackTrace[0])) {

//                stackTrace = null;

//            } else { // Verify stack trace elements are non-null.

//                for(StackTraceElement ste : stackTrace) {

//                    if (ste == null)

//                        throw new NullPointerException("null StackTraceElement in serial stream. ");

//                }

//            }

//        } else {

//            // A null stackTrace field in the serial form can result

//            // from an exception serialized without that field in

//            // older JDK releases; treat such exceptions as having

//            // empty stack traces.

//            stackTrace = UNASSIGNED_STACK.clone();

//        }

//    }

    /**

     * Write a {@code Throwable} object to a stream.

     *

     * A {@code null} stack trace field is represented in the serial

     * form as a one-element array whose element is equal to {@code

     * new StackTraceElement("", "", null, Integer.MIN_VALUE)}.

     */

//    private synchronized void writeObject(ObjectOutputStream s)

//        throws IOException {

//        // Ensure that the stackTrace field is initialized to a

//        // non-null value, if appropriate.  As of JDK 7, a null stack

//        // trace field is a valid value indicating the stack trace

//        // should not be set.

//        getOurStackTrace();

//

//        StackTraceElement[] oldStackTrace = stackTrace;

//        try {

//            if (stackTrace == null)

//                stackTrace = SentinelHolder.STACK_TRACE_SENTINEL;

//            s.defaultWriteObject();

//        } finally {

//            stackTrace = oldStackTrace;

//        }

//    }

    /**

     * Appends the specified exception to the exceptions that were

     * suppressed in order to deliver this exception. This method is

     * thread-safe and typically called (automatically and implicitly)

     * by the {@code try}-with-resources statement.