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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  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).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
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  23 
  24 /*
  25  * @test TestReclaimStringsLeaksMemory
  26  * @bug 8180048
  27  * @summary Ensure that during a Full GC interned string memory is reclaimed completely.
  28  * @requires vm.gc=="null"
  29  * @requires !vm.debug
  30  * @key gc
  31  * @library /test/lib
  32  * @modules java.base/jdk.internal.misc
  33  * @run main/othervm TestReclaimStringsLeaksMemory
  34  * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseSerialGC
  35  * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseParallelGC
  36  * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseParallelGC -XX:-UseParallelOldGC
  37  * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseConcMarkSweepGC
  38  * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseG1GC
  39  */
  40 
  41 import java.util.Arrays;
  42 import java.util.ArrayList;
  43 import java.util.regex.Pattern;
  44 import java.util.regex.Matcher;
  45 
  46 import jdk.test.lib.Asserts;
  47 import jdk.test.lib.process.OutputAnalyzer;
  48 import jdk.test.lib.process.ProcessTools;
  49 
  50 public class TestReclaimStringsLeaksMemory {
  51 
  52     // The amount of memory in kB reserved in the "Symbol" category that indicates a memory leak for
  53     // this test.
  54     public static final int ReservedThreshold = 70000;
  55 
  56     public static void main(String[] args) throws Exception {
  57         ArrayList<String> baseargs = new ArrayList(Arrays.asList( "-Xms256M",
  58                                                                   "-Xmx256M",
  59                                                                   "-Xlog:gc*",
  60                                                                   "-XX:NativeMemoryTracking=summary",
  61                                                                   "-XX:+UnlockDiagnosticVMOptions",
  62                                                                   "-XX:+PrintNMTStatistics" ));
  63         baseargs.addAll(Arrays.asList(args));
  64         baseargs.add(GCTest.class.getName());
  65         ProcessBuilder pb_default =
  66             ProcessTools.createJavaProcessBuilder(baseargs.toArray(new String[] {}));
  67         verifySymbolMemoryUsageNotTooHigh(new OutputAnalyzer(pb_default.start()));
  68     }
  69 
  70     private static void verifySymbolMemoryUsageNotTooHigh(OutputAnalyzer output) throws Exception {
  71         String stdout = output.getStdout();
  72         System.out.println(stdout);
  73 
  74         Pattern p = Pattern.compile("Symbol \\(reserved=(\\d*)");
  75         Matcher m = p.matcher(stdout);
  76 
  77         if (!m.find()) {
  78             throw new RuntimeException("Could not find Symbol memory usage in NMT output");
  79         }
  80 
  81         int reserved = Integer.parseInt(m.group(1));
  82         Asserts.assertLT(reserved, ReservedThreshold, "Reserved memory size is " + reserved + "KB which is greater than or equal to " + ReservedThreshold + "KB indicating a memory leak");
  83 
  84         output.shouldHaveExitValue(0);
  85     }
  86 
  87     static class GCTest {
  88         public static final String BaseName = "SomeRandomBaseString";
  89         public static volatile String lastString;
  90 
  91         public static void main(String [] args) {
  92             for (int iterations = 0; iterations < 20;) {
  93                 for (int i = 0; i < 1000000; i++) {
  94                     lastString = (BaseName + i).intern();
  95                 }
  96                 if (++iterations % 5 == 0) {
  97                    System.gc();
  98                 }
  99             }
 100         }
 101     }
 102 }
 103