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Java example source code file (TestMaxHeapSizeTools.java)

This example Java source code file (TestMaxHeapSizeTools.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.

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Java - Java tags/keywords

exception, mininitialmaxvalues, outputanalyzer, regex, runtimeexception, string, util, xms, xms0, xmx, xx:initialheapsize, xx\:initialheapsize\=0, xx\:initialheapsize\=4m, xx\:initialheapsize\=8m, xx\:maxheapsize\=4m

The TestMaxHeapSizeTools.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.
*/

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.ArrayList;
import java.util.Arrays;

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

class ErgoArgsPrinter {
  public static void main(String[] args) throws Exception {
    WhiteBox wb = WhiteBox.getWhiteBox();
    wb.printHeapSizes();
  }
}

final class MinInitialMaxValues {
  public long minHeapSize;
  public long initialHeapSize;
  public long maxHeapSize;

  public long minAlignment;
  public long maxAlignment;
}

class TestMaxHeapSizeTools {

  public static void checkMinInitialMaxHeapFlags(String gcflag) throws Exception {
    checkInvalidMinInitialHeapCombinations(gcflag);
    checkValidMinInitialHeapCombinations(gcflag);
    checkInvalidInitialMaxHeapCombinations(gcflag);
    checkValidInitialMaxHeapCombinations(gcflag);
  }

  public static void checkMinInitialErgonomics(String gcflag) throws Exception {
    // heap sizing ergonomics use the value NewSize + OldSize as default values
    // for ergonomics calculation. Retrieve these values.
    long[] values = new long[2];
    getNewOldSize(gcflag, values);

    // we check cases with values smaller and larger than this default value.
    long newPlusOldSize = values[0] + values[1];
    long smallValue = newPlusOldSize / 2;
    long largeValue = newPlusOldSize * 2;
    long maxHeapSize = largeValue + (2 * 1024 * 1024);

    // -Xms is not set
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize }, values, -1, -1);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-XX:InitialHeapSize=" + smallValue }, values, -1, smallValue);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-XX:InitialHeapSize=" + largeValue }, values, -1, largeValue);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-XX:InitialHeapSize=0" }, values, -1, -1);

    // -Xms is set to zero
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms0" }, values, -1, -1);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms0", "-XX:InitialHeapSize=" + smallValue }, values, -1, smallValue);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms0", "-XX:InitialHeapSize=" + largeValue }, values, -1, largeValue);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms0", "-XX:InitialHeapSize=0" }, values, -1, -1);

    // -Xms is set to small value
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms" + smallValue }, values, -1, -1);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms" + smallValue, "-XX:InitialHeapSize=" + smallValue }, values, smallValue, smallValue);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms" + smallValue, "-XX:InitialHeapSize=" + largeValue }, values, smallValue, largeValue);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms" + smallValue, "-XX:InitialHeapSize=0" }, values, smallValue, -1);

    // -Xms is set to large value
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms" + largeValue }, values, largeValue, largeValue);
    checkErgonomics(new String[] { gcflag, "-Xmx" + maxHeapSize, "-Xms" + largeValue, "-XX:InitialHeapSize=0" }, values, largeValue, -1);
  }

  private static long align_up(long value, long alignment) {
    long alignmentMinusOne = alignment - 1;
    return (value + alignmentMinusOne) & ~alignmentMinusOne;
  }

  private static void getNewOldSize(String gcflag, long[] values) throws Exception {
    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(gcflag,
      "-XX:+PrintFlagsFinal", "-version");
    OutputAnalyzer output = new OutputAnalyzer(pb.start());
    output.shouldHaveExitValue(0);

    String stdout = output.getStdout();
    values[0] = getFlagValue(" NewSize", stdout);
    values[1] = getFlagValue(" OldSize", stdout);
  }

  public static void checkGenMaxHeapErgo(String gcflag) throws Exception {
    TestMaxHeapSizeTools.checkGenMaxHeapSize(gcflag, 3);
    TestMaxHeapSizeTools.checkGenMaxHeapSize(gcflag, 4);
    TestMaxHeapSizeTools.checkGenMaxHeapSize(gcflag, 5);
  }

  private static void checkInvalidMinInitialHeapCombinations(String gcflag) throws Exception {
    expectError(new String[] { gcflag, "-Xms8M", "-XX:InitialHeapSize=4M", "-version" });
  }

  private static void checkValidMinInitialHeapCombinations(String gcflag) throws Exception {
    expectValid(new String[] { gcflag, "-XX:InitialHeapSize=8M", "-Xms4M", "-version" });
    expectValid(new String[] { gcflag, "-Xms4M", "-XX:InitialHeapSize=8M", "-version" });
    expectValid(new String[] { gcflag, "-XX:InitialHeapSize=8M", "-Xms8M", "-version" });
    // the following is not an error as -Xms sets both minimal and initial heap size
    expectValid(new String[] { gcflag, "-XX:InitialHeapSize=4M", "-Xms8M", "-version" });
  }

  private static void checkInvalidInitialMaxHeapCombinations(String gcflag) throws Exception {
    expectError(new String[] { gcflag, "-XX:MaxHeapSize=4M", "-XX:InitialHeapSize=8M", "-version" });
    expectError(new String[] { gcflag, "-XX:InitialHeapSize=8M", "-XX:MaxHeapSize=4M", "-version" });
  }

  private static void checkValidInitialMaxHeapCombinations(String gcflag) throws Exception {
    expectValid(new String[] { gcflag, "-XX:InitialHeapSize=4M", "-XX:MaxHeapSize=8M", "-version" });
    expectValid(new String[] { gcflag, "-XX:MaxHeapSize=8M", "-XX:InitialHeapSize=4M", "-version" });
    expectValid(new String[] { gcflag, "-XX:MaxHeapSize=4M", "-XX:InitialHeapSize=4M", "-version" });
    // a value of "0" for initial heap size means auto-detect
    expectValid(new String[] { gcflag, "-XX:MaxHeapSize=4M", "-XX:InitialHeapSize=0M", "-version" });
  }

  private static long valueAfter(String source, String match) {
    int start = source.indexOf(match) + match.length();
    String tail = source.substring(start).split(" ")[0];
    return Long.parseLong(tail);
  }

  /**
   * Executes a new VM process with the given class and parameters.
   * @param vmargs Arguments to the VM to run
   * @param classname Name of the class to run
   * @param arguments Arguments to the class
   * @param useTestDotJavaDotOpts Use test.java.opts as part of the VM argument string
   * @return The OutputAnalyzer with the results for the invocation.
   */
  public static OutputAnalyzer runWhiteBoxTest(String[] vmargs, String classname, String[] arguments, boolean useTestDotJavaDotOpts) throws Exception {
    ArrayList<String> finalargs = new ArrayList();

    String[] whiteboxOpts = new String[] {
      "-Xbootclasspath/a:.",
      "-XX:+UnlockDiagnosticVMOptions", "-XX:+WhiteBoxAPI",
      "-cp", System.getProperty("java.class.path"),
    };

    if (useTestDotJavaDotOpts) {
      // System.getProperty("test.java.opts") is '' if no options is set,
      // we need to skip such a result
      String[] externalVMOpts = new String[0];
      if (System.getProperty("test.java.opts") != null && System.getProperty("test.java.opts").length() != 0) {
        externalVMOpts = System.getProperty("test.java.opts").split(" ");
      }
      finalargs.addAll(Arrays.asList(externalVMOpts));
    }

    finalargs.addAll(Arrays.asList(vmargs));
    finalargs.addAll(Arrays.asList(whiteboxOpts));
    finalargs.add(classname);
    finalargs.addAll(Arrays.asList(arguments));

    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(finalargs.toArray(new String[0]));
    OutputAnalyzer output = new OutputAnalyzer(pb.start());
    output.shouldHaveExitValue(0);

    return output;
  }

  private static void getMinInitialMaxHeap(String[] args, MinInitialMaxValues val) throws Exception {
    OutputAnalyzer output = runWhiteBoxTest(args, ErgoArgsPrinter.class.getName(), new String[] {}, false);

    // the output we watch for has the following format:
    //
    // "Minimum heap X Initial heap Y Maximum heap Z Min alignment A Max Alignment B"
    //
    // where A, B, X, Y and Z are sizes in bytes.
    // Unfortunately there is no other way to retrieve the minimum heap size and
    // the alignments.

    Matcher m = Pattern.compile("Minimum heap \\d+ Initial heap \\d+ Maximum heap \\d+ Min alignment \\d+ Max alignment \\d+").
      matcher(output.getStdout());
    if (!m.find()) {
      throw new RuntimeException("Could not find heap size string.");
    }

    String match = m.group();

    // actual values
    val.minHeapSize = valueAfter(match, "Minimum heap ");
    val.initialHeapSize = valueAfter(match, "Initial heap ");
    val.maxHeapSize = valueAfter(match, "Maximum heap ");
    val.minAlignment = valueAfter(match, "Min alignment ");
    val.maxAlignment = valueAfter(match, "Max alignment ");
  }

  /**
   * Verify whether the VM automatically synchronizes minimum and initial heap size if only
   * one is given for the GC specified.
   */
  public static void checkErgonomics(String[] args, long[] newoldsize,
    long expectedMin, long expectedInitial) throws Exception {

    MinInitialMaxValues v = new MinInitialMaxValues();
    getMinInitialMaxHeap(args, v);

    if ((expectedMin != -1) && (align_up(expectedMin, v.minAlignment) != v.minHeapSize)) {
      throw new RuntimeException("Actual minimum heap size of " + v.minHeapSize +
        " differs from expected minimum heap size of " + expectedMin);
    }

    if ((expectedInitial != -1) && (align_up(expectedInitial, v.minAlignment) != v.initialHeapSize)) {
      throw new RuntimeException("Actual initial heap size of " + v.initialHeapSize +
        " differs from expected initial heap size of " + expectedInitial);
    }

    // always check the invariant min <= initial <= max heap size
    if (!(v.minHeapSize <= v.initialHeapSize && v.initialHeapSize <= v.maxHeapSize)) {
      throw new RuntimeException("Inconsistent min/initial/max heap sizes, they are " +
        v.minHeapSize + "/" + v.initialHeapSize + "/" + v.maxHeapSize);
    }
  }

  /**
   * Verify whether the VM respects the given maximum heap size in MB for the
   * GC specified.
   * @param gcflag The garbage collector to test as command line flag. E.g. -XX:+UseG1GC
   * @param maxHeapSize the maximum heap size to verify, in MB.
   */
  public static void checkGenMaxHeapSize(String gcflag, long maxHeapsize) throws Exception {
    final long K = 1024;

    MinInitialMaxValues v = new MinInitialMaxValues();
    getMinInitialMaxHeap(new String[] { gcflag, "-XX:MaxHeapSize=" + maxHeapsize + "M" }, v);

    long expectedHeapSize = align_up(maxHeapsize * K * K, v.maxAlignment);
    long actualHeapSize = v.maxHeapSize;

    if (actualHeapSize > expectedHeapSize) {
      throw new RuntimeException("Heap has " + actualHeapSize  +
        " bytes, expected to be less than " + expectedHeapSize);
    }
  }

  private static long getFlagValue(String flag, String where) {
    Matcher m = Pattern.compile(flag + "\\s+:?=\\s+\\d+").matcher(where);
    if (!m.find()) {
      throw new RuntimeException("Could not find value for flag " + flag + " in output string");
    }
    String match = m.group();
    return Long.parseLong(match.substring(match.lastIndexOf(" ") + 1, match.length()));
  }

  private static void shouldContainOrNot(OutputAnalyzer output, boolean contains, String message) throws Exception {
    if (contains) {
      output.shouldContain(message);
    } else {
      output.shouldNotContain(message);
    }
  }

  private static void expect(String[] flags, boolean hasWarning, boolean hasError, int errorcode) throws Exception {
    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(flags);
    OutputAnalyzer output = new OutputAnalyzer(pb.start());
    shouldContainOrNot(output, hasWarning, "Warning");
    shouldContainOrNot(output, hasError, "Error");
    output.shouldHaveExitValue(errorcode);
  }

  private static void expectError(String[] flags) throws Exception {
    expect(flags, false, true, 1);
  }

  private static void expectValid(String[] flags) throws Exception {
    expect(flags, false, false, 0);
  }
}

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