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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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23
24/*
25 * @test TestSelectDefaultGC
26 * @summary Test selection of GC when no GC option is specified
27 * @bug 8068582
28 * @key gc
29 * @library /test/lib
30 * @requires vm.gc=="null"
31 * @modules java.base/jdk.internal.misc
32 *          java.management
33 * @run driver TestSelectDefaultGC
34 */
35
36import jdk.test.lib.Platform;
37import jdk.test.lib.process.OutputAnalyzer;
38import jdk.test.lib.process.ProcessTools;
39
40import java.util.regex.*;
41
42public class TestSelectDefaultGC {
43    public static void assertVMOption(OutputAnalyzer output, String option, boolean value) {
44        output.shouldMatch(" " + option + " .*=.* " + value + " ");
45    }
46
47    public static void testDefaultGC(boolean actAsServer) throws Exception {
48        String[] args = new String[] {
49          "-XX:" + (actAsServer ? "+" : "-") + "AlwaysActAsServerClassMachine",
50          "-XX:" + (actAsServer ? "-" : "+") + "NeverActAsServerClassMachine",
51          "-XX:+PrintFlagsFinal",
52          "-version"
53        };
54
55        // Start VM without specifying GC
56        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(args);
57        OutputAnalyzer output = new OutputAnalyzer(pb.start());
58        output.shouldHaveExitValue(0);
59
60        final boolean isServer = actAsServer;
61
62        // Verify GC selection
63        // G1 is default for server class machines
64        assertVMOption(output, "UseG1GC",            isServer);
65        // Serial is default for non-server class machines
66        assertVMOption(output, "UseSerialGC",        !isServer);
67        // CMS is never default
68        assertVMOption(output, "UseConcMarkSweepGC", false);
69    }
70
71    public static void main(String[] args) throws Exception {
72        // Test server class machine
73        testDefaultGC(false);
74
75        // Test non-server class machine
76        testDefaultGC(true);
77    }
78}
79