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

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

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

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 */

/*

 * @test

 * @key stress

 *

 * @summary converted from VM testbase nsk/stress/except/except002.

 * VM testbase keywords: [stress, diehard, slow, nonconcurrent, quick]

 * VM testbase readme:

 * DESCRIPTION

 *     This checks if various exceptions are thrown (and caught) correctly

 *     when there apparently are no free space in the heap to allocate new

 *     Throwable instance.

 *     The test tries to occupy all of memory available in the heap by allocating

 *     lots of new Object() instances. Instances of the type Object are the smallest

 *     objects, so they apparently should occupy most fine-grained fragments in the

 *     heap and leave no free space for new Throwable instance. After that, the test

 *     provokes various exceptions (e.g.: by executing integer division by 0 and so

 *     on), and checks if appropriate exceptions are thrown.

 * COMMENTS

 *     The test needs a lot of memory to start up, so it should not run under older

 *     JDK 1.1.x release due to its poorer heap utilization. Also, some checks are

 *     skipped when testing classic VM, because OutOfMemoryError is correctly thrown

 *     instead of target exception.

 *     When the test is being self-initiating (i.e.: eating heap), memory occupation

 *     is terminated if memory allocation slows down crucially. This is a workaround

 *     intended to avoid the HotSpot bug:

 *         #4248801 (P1/S5) slow memory allocation when heap is almost exhausted

 *     There is also a workaround involved to avoid the following bugs known

 *     for HotSpot and for classic VM:

 *         #4239841 (P1/S5) 1.1: poor garbage collector performance  (HotSpot bug)

 *         #4245060 (P4/S5) poor garbage collector performance       (Classic VM bug)

 *     However, printing of the test's error messages, warnings, and of execution

 *     trace fails under JDK 1.2 for Win32 even so. If the test fails due to this

 *     problem, exit status 96 is returned instead of 97.

 *     JDK 1.3 classic VM for Sparc may crash (core dump) due to the known bug:

 *         #4245057 (P2/S3) VM crashes when heap is exhausted

 *

 * @run main/othervm -Xms50M -Xmx200M nsk.stress.except.except002

 */

package nsk.stress.except;

import java.io.PrintStream;

/**

 * This checks if various exceptions are thrown (and caught) correctly

 * when there apparently are no free space in the heap to allocate new

 * <code>Throwable</code> instance.

 * <p>

 * <p>The test tries to occupy all of memory available in the heap by

 * allocating lots of new <code>Object()</code> instances. Instances of the

 * type <code>Object</code> are the smallest objects, so they apparently should

 * occupy most fine-grained fragments in the heap and leave no free space for

 * new <code>Throwable</code> instance. After that, the test provokes various

 * exceptions (e.g.: by executing integer division by 0 and so on), and checks

 * if appropriate exceptions are thrown.

 * <p>

 * <p>Note, that memory occupation is terminated if memory allocation slows

 * down crucially. This is a workaround intended to avoid the HotSpot bug:

 * <br>&nbsp;&nbsp;

 * #4248801 (P1/S5) slow memory allocation when heap is almost exhausted

 * <p>

 * <p>There is also a workaround involved to avoid the following bugs known

 * for HotSpot and for classic VM:

 * <br>&nbsp;&nbsp;

 * #4239841 (P1/S5) 1.1: poor garbage collector performance

 * <br>&nbsp;&nbsp;

 * #4245060 (P4/S5) poor garbage collector performance

 * <br>However, printing of the test's error messages, warnings, and of

 * execution trace may fail even so. If the test fails due to poor GC

 * performance, exit status 96 is returned instead of 97.

 * <p>

 * <p>Also note, that the test needs a lot of memory to start up, so it should

 * not run under older JDK 1.1.x release due to its poor heap utilization.

 */

public class except002 {

    /**

     * Either allow or supress printing of execution trace.

     */

    private static boolean TRACE_ON = false;

    /**

     * Either allow or supress printing of warning messages.

     */

    private static final boolean WARN_ON = true;

    /*

     * Storage for a lot of tiny objects

     * "static volatile" keywords are for preventing heap optimization

     */

    public static volatile Object pool[] = null;

    /**

     * Temporary <code>log</code> for error messages, warnings and/or execution trace.

     *

     * @see #messages

     */

    private static String log[] = new String[1000]; // up to 1000 messages

    /**

     * How many <code>messages</code> were submitted to the <code>log</code>.

     *

     * @see #log

     */

    private static int messages = 0;

    /**

     * Re-call to the method <code>run(out)</code> (ignore <code>args[]</code>),

     * and print the test summary - either test passed of failed.

     */

    public static int run(String args[], PrintStream out) {

        if (args.length > 0) {

            if (args[0].toLowerCase().startsWith("-v"))

                TRACE_ON = true;

        }

        int exitCode = run(out);

        pool = null;

        System.gc();

        // Print the log[] and the test summary:

        try {

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

                out.println(log[i]);

            if (exitCode == 0) {

                if (TRACE_ON)

                    out.println("Test passed.");

            } else

                out.println("Test failed.");

        } catch (OutOfMemoryError oome) {

            // Poor performance of garbage collector:

            exitCode = 1;

        }

        return exitCode;

    }

    /**

     * Allocate as much <code>Object</code> instances as possible to bring JVM

     * into stress, and then check if exceptions are correctly thrown accordingly

     * to various situations like integer division by 0, etc.

     */

    private static int run(PrintStream out) {

        out.println("# While printing this message, JVM seems to initiate the output");

        out.println("# stream, so that it will not need more memory to print later,");

        out.println("# when the heap would fail to provide more memory.");

        out.println("# ");

        out.println("# Note, that the test maintains especial static log[] field in");

        out.println("# order to avoid printing when the heap seems exhausted.");

        out.println("# Nevertheless, printing could arise OutOfMemoryError even");

        out.println("# after all the memory allocated by the test is released.");

        out.println("# ");

        out.println("# That problem is caused by the known JDK/HotSpot bugs:");

        out.println("#     4239841 (P1/S5) 1.1: poor garbage collector performance");

        out.println("#     4245060 (P4/S5) poor garbage collector performance");

        out.println("# ");

        out.println("# This message is just intended to work-around that problem.");

        out.println("# If printing should fail even so, the test will return the");

        out.println("# exit status 96 instead of 97 to indicate the problem.");

        // Prepare some items, which will be used by the test:

        Object trash = null;

        // Sum up exit code:

        int exitCode = 0; // apparently PASSED

        int skipped = 0;  // some checks may correctly suffer OutOfMemoryError

        // Allocate repository for a lots of tiny objects:

        for (int size = 1 << 30; size > 0 && pool == null; size >>= 1)

            try {

                pool = new Object[size];

            } catch (OutOfMemoryError oome) {

            }

        if (pool == null)

            throw new Error("HS bug: cannot allocate new Object[1]");

        int poolSize = pool.length;

        int index = 0;

        // Sum up time spent, when it was hard to JVM to allocate next object

        // (i.e.: when JVM has spent more than 1 second to allocate new object):

        double totalDelay = 0;

        long timeMark = System.currentTimeMillis();

        try {

            for (; index < poolSize; index++) {

                //-------------------------

                pool[index] = new Object();

                long nextTimeMark = System.currentTimeMillis();

                long elapsed = nextTimeMark - timeMark;

                timeMark = nextTimeMark;

                //----------------------

                if (elapsed > 1000) {

                    double seconds = elapsed / 1000.0;

                    if (TRACE_ON)

                        out.println(

                                "pool[" + index + "]=new Object(); // elapsed " + seconds + "s");

                    totalDelay += seconds;

                    if (totalDelay > 60) {

                        if (TRACE_ON)

                            out.println(

                                    "Memory allocation became slow; so, heap seems exhausted.");

                        break;

                    }

                }

            }

        } catch (OutOfMemoryError oome) {

            if (TRACE_ON)

                log[messages++] = "Heap seems exhausted - OutOfMemoryError thrown.";

            // Do not release any byte once allocated:

            pool[index++] = oome;

        }

        if (index > poolSize - 1000) {

            if (WARN_ON)

                log[messages++] = "Warning: pool[] is full; so, checks would not be enough hard...";

        }

        // Check ClassNotFoundException (positive):

        try {

            trash = Class.forName("nsk.stress.except.except002$Abra$Cadabra"); //   correct - should pass

//          trash = Class.forName("nsk.stress.except.except002.Abra.Cadabra"); // incorrect - should fail

            if (TRACE_ON)

                log[messages++] = "Success: ClassNotFoundException (positive)";

        } catch (ClassNotFoundException cnfe) {

            log[messages++] = "Failure: ClassNotFoundException (positive)";

            exitCode = 2;

        } catch (OutOfMemoryError oome) {

            if (WARN_ON)

                log[messages++] = "Skipped: ClassNotFoundException (positive)";

            skipped++;

        }

        return exitCode;

    }

    /**

     * Re-call to <code>run(args,out)</code>, and return JCK-like exit status.

     * (The stream <code>out</code> is assigned to <code>System.out</code> here.)

     *

     * @see #run(String[], PrintStream)

     */

    public static void main(String args[]) {

            // Last try. If there is some exception outside the code, test should end correctly

            @Override

            public void uncaughtException(Thread t, Throwable e) {

                try {

                    pool = null;

                    log = null;

                    System.gc();

                    if (e instanceof OutOfMemoryError) {

                        try {

                            System.out.println("OOME : Test Skipped");

                            System.exit(0);

                        } catch (Throwable ignore) {

                        } // No code in the handler can provoke correct exceptions.

                    } else {

                        e.printStackTrace();

                        throw (RuntimeException) e;

                    }

                } catch (OutOfMemoryError oome) {

                }

            }

        });

        int exitCode = run(args, System.out);

        System.exit(exitCode + 95);

        // JCK-like exit status.

    }

    /**

     * This class should be used to check <code>ClassNotFoundException</code>

     * and <code>IllegalAccessException</code>.

     */

    private static class Abra {

        /**

         * Will try to incorrectly find this class as <code>Cadabra</code>

         * instead of <code>Abra$Cadabra</code>.

         */

        public static class Cadabra {

        }

    }

}