ClassHistogramTest.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
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 */

import org.testng.annotations.Test;

import java.util.regex.Pattern;

import com.oracle.java.testlibrary.OutputAnalyzer;
import com.oracle.java.testlibrary.dcmd.CommandExecutor;
import com.oracle.java.testlibrary.dcmd.JMXExecutor;

/*
 * @test
 * @summary Test of diagnostic command GC.class_histogram
 * @library /testlibrary
 * @modules java.base/sun.misc
 *          java.compiler
 *          java.management
 *          jdk.jvmstat/sun.jvmstat.monitor
 * @build com.oracle.java.testlibrary.*
 * @build com.oracle.java.testlibrary.dcmd.*
 * @run testng ClassHistogramTest
 */
public class ClassHistogramTest {
    public static class TestClass {}
    public static TestClass[] instances = new TestClass[1024];
    protected String classHistogramArgs = "";

    static {
        for (int i = 0; i < instances.length; ++i) {
            instances[i] = new TestClass();
        }
    }

    public void run(CommandExecutor executor) {
        OutputAnalyzer output = executor.execute("GC.class_histogram " + classHistogramArgs);

        /*
         * example output:
         *   num     #instances         #bytes  class name
         *  ----------------------------------------------
         *     1:          1647        1133752  [B
         *     2:          6198         383168  [C
         *     3:          1464         165744  java.lang.Class
         *     4:          6151         147624  java.lang.String
         *     5:          2304          73728  java.util.concurrent.ConcurrentHashMap$Node
         *     6:          1199          64280  [Ljava.lang.Object;
         * ...
         */

        /* Require at least one java.lang.Class */
        output.shouldMatch("^\\s+\\d+:\\s+\\d+\\s+\\d+\\s+java.lang.Class\\s*$");

        /* Require at least one java.lang.String */
        output.shouldMatch("^\\s+\\d+:\\s+\\d+\\s+\\d+\\s+java.lang.String\\s*$");

        /* Require at least one java.lang.Object */
        output.shouldMatch("^\\s+\\d+:\\s+\\d+\\s+\\d+\\s+java.lang.Object\\s*$");

        /* Require at exactly one TestClass[] */
        output.shouldMatch("^\\s+\\d+:\\s+1\\s+\\d+\\s+" +
                Pattern.quote(TestClass[].class.getName()) + "\\s*$");

        /* Require at exactly 1024 TestClass */
        output.shouldMatch("^\\s+\\d+:\\s+1024\\s+\\d+\\s+" +
                Pattern.quote(TestClass.class.getName()) + "\\s*$");
    }

    @Test
    public void jmx() {
        run(new JMXExecutor());
    }
}