test/hotspot/jtreg/runtime/ClassUnload/UnloadTest.java

*** 21,38 ****
   * questions.
   */
  
  /*
   * @test UnloadTest
   * @requires vm.opt.final.ClassUnloading
   * @modules java.base/jdk.internal.misc
   * @library /runtime/testlibrary /test/lib
   * @library classes
   * @build sun.hotspot.WhiteBox test.Empty
   * @run driver ClassFileInstaller sun.hotspot.WhiteBox
   *                              sun.hotspot.WhiteBox$WhiteBoxPermission
!  * @run main/othervm -Xbootclasspath/a:. -Xmn8m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI UnloadTest
   */
  import sun.hotspot.WhiteBox;
  
  /**
   * Test that verifies that classes are unloaded when they are no longer reachable.
--- 21,39 ----
   * questions.
   */
  
  /*
   * @test UnloadTest
+  * @bug 8210559
   * @requires vm.opt.final.ClassUnloading
   * @modules java.base/jdk.internal.misc
   * @library /runtime/testlibrary /test/lib
   * @library classes
   * @build sun.hotspot.WhiteBox test.Empty
   * @run driver ClassFileInstaller sun.hotspot.WhiteBox
   *                              sun.hotspot.WhiteBox$WhiteBoxPermission
!  * @run main/othervm -Xbootclasspath/a:. -Xmn8m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xlog:class+unload=debug UnloadTest
   */
  import sun.hotspot.WhiteBox;
  
  /**
   * Test that verifies that classes are unloaded when they are no longer reachable.
*** 58,67 ****
--- 59,76 ----
          Class<?> c = cl.loadClass(className);
          Object o = c.newInstance();
  
          ClassUnloadCommon.failIf(!wb.isClassAlive(className), "should be live here");
  
+         String loaderName = cl.getName();
+         int loadedRefcount = wb.getSymbolRefcount(loaderName);
+         System.out.println("Refcount of symbol " + loaderName + " is " + loadedRefcount);
+ 
          cl = null; c = null; o = null;
          ClassUnloadCommon.triggerUnloading();
          ClassUnloadCommon.failIf(wb.isClassAlive(className), "should have been unloaded");
+ 
+         int unloadedRefcount = wb.getSymbolRefcount(loaderName);
+         System.out.println("Refcount of symbol " + loaderName + " is " + unloadedRefcount);
+         ClassUnloadCommon.failIf(unloadedRefcount != (loadedRefcount - 1), "Refcount must be decremented");
      }
  }