1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
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  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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 
  36 import jdk.test.lib.Platform;
  37 import jdk.test.lib.process.OutputAnalyzer;
  38 import jdk.test.lib.process.ProcessTools;
  39 
  40 import java.util.regex.*;
  41 
  42 public 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         assertVMOption(output, "UseParNewGC",        false);
  70     }
  71 
  72     public static void main(String[] args) throws Exception {
  73         // Test server class machine
  74         testDefaultGC(false);
  75 
  76         // Test non-server class machine
  77         testDefaultGC(true);
  78     }
  79 }