Quelle FinalizerHistogramTest.java Sprache: JAVA

/*
* Copyright (c) 2015, 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.
*
* 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.
*/

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

import java.lang.reflect.Method;
import java.lang.reflect.Field;

/*
* @test
* @summary Unit test for FinalizerHistogram
* @modules java.base/java.lang.ref:open
* @run main FinalizerHistogramTest
*/

public class FinalizerHistogramTest {
    static ReentrantLock lock = new ReentrantLock();
    static volatile int wasInitialized = 0;
    static volatile int wasTrapped = 0;
    static final int objectsCount = 1000;

    static class MyObject {
        public MyObject() {
            // Make sure object allocation/deallocation is not optimized out
            wasInitialized += 1;
        }

        protected void finalize() {
            // Trap the object in a finalization queue
            wasTrapped += 1;
            lock.lock();
        }
    }

    public static void main(String[] argvs) {
        try {
            lock.lock();
            for(int i = 0; i < objectsCount; ++i) {
                new MyObject();
            }
            System.out.println("Objects intialized: " + objectsCount);
            System.gc();
            while(wasTrapped < 1);

            Class<?> klass = Class.forName("java.lang.ref.FinalizerHistogram");

            Method m = klass.getDeclaredMethod("getFinalizerHistogram");
            m.setAccessible(true);
            Object entries[] = (Object[]) m.invoke(null);

            Class<?> entryKlass = Class.forName("java.lang.ref.FinalizerHistogram$Entry");
            Field name = entryKlass.getDeclaredField("className");
            name.setAccessible(true);
            Field count = entryKlass.getDeclaredField("instanceCount");
            count.setAccessible(true);

            System.out.println("Unreachable instances waiting for finalization");
            System.out.println("#instances class name");
            System.out.println("-----------------------");

            boolean found = false;
            for (Object entry : entries) {
                Object e = entryKlass.cast(entry);
                System.out.printf("%10d %s\n", count.get(e), name.get(e));
                if (((String) name.get(e)).indexOf("MyObject") != -1 ) {
                    found = true;
                }
            }

            if (!found) {
                throw new RuntimeException("MyObject is not found in test output");
            }

            System.out.println("Test PASSED");
        } catch(Exception e) {
           System.err.println("Test failed with " + e);
           e.printStackTrace(System.err);
           throw new RuntimeException("Test failed");
        } finally {
            lock.unlock();
        }
    }
}

quality89%

¤ Dauer der Verarbeitung: 0.14 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.