GetInitializedClassCount.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 2 along with this work; if not, write to the Free Software Foundation,
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/*
 * @test
 * @bug     4858522
 * @summary Basic unit test of HotspotClassLoadingMBean.getInitializedClassCount()
 * @author  Steve Bohne
 *
 * @run main/othervm -XX:+UsePerfData GetInitializedClassCount
 */

/*
 * This test is just a sanity check and does not check for the correct value.
 */

import sun.management.*;

public class GetInitializedClassCount {

    private static HotspotClassLoadingMBean mbean =
        (HotspotClassLoadingMBean)ManagementFactoryHelper.getHotspotClassLoadingMBean();

    // Careful with these values.
    private static final long MIN_VALUE_FOR_PASS = 1;
    private static final long MAX_VALUE_FOR_PASS = Long.MAX_VALUE;

    private static boolean trace = false;

    public static void main(String args[]) throws Exception {
        if (args.length > 0 && args[0].equals("trace")) {
            trace = true;
        }

        long value = mbean.getInitializedClassCount();

        if (trace) {
            System.out.println("Initialized class count: " + value);
        }

        if (value < MIN_VALUE_FOR_PASS || value > MAX_VALUE_FOR_PASS) {
            throw new RuntimeException("Initialized class count " +
                                       "illegal value: " + value + " " +
                                       "(MIN = " + MIN_VALUE_FOR_PASS + "; " +
                                       "MAX = " + MAX_VALUE_FOR_PASS + ")");
        }

        // Initialize a class
        Class.forName("ClassToInitialize0");

        long value2 = mbean.getInitializedClassCount();

        if (trace) {
            System.out.println("Initialized class count2: " + value2);
        }

        // If new count does not reflect that at least one class has
        // been initialized, throw an exception.  We don't check that
        // _exactly_ one class has been initialized because another
        // thread may (rarely) have also done some class initialization.
        if (value2 < value + 1) {
            throw new RuntimeException("Initialized class count " +
                                       "did not increase " +
                                       "(value = " + value + "; " +
                                       "value2 = " + value2 + ")");
        }

        System.out.println("Test passed.");
    }
}

class ClassToInitialize0 {
    static int i = 0;
    static {
        i = 1;
    }
}