Quelle  Test1902.java

/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package art;

public class Test1902 {
    public static final Object lock = new Object();

    public static volatile boolean OTHER_THREAD_CONTINUE = true;
    public static volatile boolean OTHER_THREAD_DID_SOMETHING = true;
    public static volatile boolean OTHER_THREAD_STARTED = false;

    public static class OtherThread implements Runnable {
        @Override
        public void run() {
            OTHER_THREAD_STARTED = true;
            while (OTHER_THREAD_CONTINUE) {
                OTHER_THREAD_DID_SOMETHING = true;
            }
        }
    }

    public static void waitFor(long millis) {
        try {
            lock.wait(millis);
        } catch (Exception e) {
            System.out.println("Unexpected error: " + e);
            e.printStackTrace();
        }
    }

    public static void waitForSuspension(Thread target) {
        while (!Suspension.isSuspended(target)) {
            waitFor(100);
        }
    }

    public static void waitForStart() {
        while (!OTHER_THREAD_STARTED) {
            waitFor(100);
        }
    }


    public static void run() {
        synchronized (lock) {
            Thread other = new Thread(new OtherThread(), "TARGET THREAD");
            try {
                other.start();

                waitForStart();

                // Try to resume ourself.
                try {
                    Suspension.resume(Thread.currentThread());
                } catch (Exception e) {
                    if (!e.getMessage().equals("JVMTI_ERROR_THREAD_NOT_SUSPENDED")) {
                        System.out.println("incorrect error for resuming a non-suspended thread");
                    }
                }
                try {
                    Suspension.resume(other);
                } catch (Exception e) {
                    if (!e.getMessage().equals("JVMTI_ERROR_THREAD_NOT_SUSPENDED")) {
                        System.out.println("incorrect error for resuming a non-suspended thread");
                    }
                }

                Suspension.suspend(other);
                // Wait 1 second for the other thread to suspend.
                waitForSuspension(other);
                OTHER_THREAD_DID_SOMETHING = false;
                // Wait a second to see if anything happens.
                waitFor(1000);

                if (OTHER_THREAD_DID_SOMETHING) {
                    System.out.println("Looks like other thread did something while suspended!");
                }
                // Resume always.
                Suspension.resume(other);

                // Wait another second.
                waitFor(1000);

                if (!OTHER_THREAD_DID_SOMETHING) {
                    System.out.println("Doesn't look like the thread unsuspended!");
                }

                // Stop the other thread.
                OTHER_THREAD_CONTINUE = false;
                // Wait for 1 second for it to die.
                other.join(1000);

                if (other.isAlive()) {
                    System.out.println("other thread didn't terminate in a reasonable time!");
                    Runtime.getRuntime().halt(1);
                }
            } catch (Throwable t) {
                System.out.println(
                        "something was thrown. Runtime might be in unrecoverable state: " + t);
                t.printStackTrace();
                Runtime.getRuntime().halt(2);
            }
        }
    }
}