Java example source code file (ThreadedMallocTestType.java)

This example Java source code file (ThreadedMallocTestType.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

api, call, exception, nmtwaitfordatamerge, outputanalyzer, processbuilder, string, test, thread, threadedmalloctesttype, whitebox

The ThreadedMallocTestType.java Java example source code

/*
 * Copyright (c) 2013, 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.
 */

/*
 * @test
 * @key nmt jcmd
 * @library /testlibrary /testlibrary/whitebox
 * @build ThreadedMallocTestType
 * @run main ClassFileInstaller sun.hotspot.WhiteBox
 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:NativeMemoryTracking=detail ThreadedMallocTestType
 */

import com.oracle.java.testlibrary.*;
import sun.hotspot.WhiteBox;

public class ThreadedMallocTestType {
  public static long memAlloc1;
  public static long memAlloc2;
  public static long memAlloc3;

  public static void main(String args[]) throws Exception {
    OutputAnalyzer output;
    final WhiteBox wb = WhiteBox.getWhiteBox();

    // Grab my own PID
    String pid = Integer.toString(ProcessTools.getProcessId());
    ProcessBuilder pb = new ProcessBuilder();

    Thread allocThread = new Thread() {
      public void run() {
        // Alloc memory using the WB api
        memAlloc1 = wb.NMTMalloc(128 * 1024);
        memAlloc2 = wb.NMTMalloc(256 * 1024);
        memAlloc3 = wb.NMTMalloc(512 * 1024);
      }
    };

    allocThread.start();
    allocThread.join();

    // Use WB API to ensure that all data has been merged before we continue
    if (!wb.NMTWaitForDataMerge()) {
      throw new Exception("Call to WB API NMTWaitForDataMerge() failed");
    }

    // Run 'jcmd <pid> VM.native_memory summary'
    pb.command(new String[] { JDKToolFinder.getJDKTool("jcmd"), pid, "VM.native_memory", "summary"});
    output = new OutputAnalyzer(pb.start());
    output.shouldContain("Test (reserved=896KB, committed=896KB)");

    Thread freeThread = new Thread() {
      public void run() {
        // Free the memory allocated by NMTMalloc
        wb.NMTFree(memAlloc1);
        wb.NMTFree(memAlloc2);
        wb.NMTFree(memAlloc3);
      }
    };

    freeThread.start();
    freeThread.join();

    // Use WB API to ensure that all data has been merged before we continue
    if (!wb.NMTWaitForDataMerge()) {
      throw new Exception("Call to WB API NMTWaitForDataMerge() failed");
    }

    output = new OutputAnalyzer(pb.start());
    output.shouldNotContain("Test (reserved=");
  }
}