test/hotspot/jtreg/vmTestbase/nsk/jdwp/ReferenceType/Instances/instances001/instances001.java

*** 58,67 ****
--- 58,68 ----
   *         - create command with typeID = -1, expect INVALID_OBJECT error
   *         - create command with threadID instead of referenceTypeID, expect INVALID_CLASS error
   *     Finally, debugger sends debuggee signal to quit, waits for it exits
   *     and exits too with the proper exit code.
   *
+  * @requires vm.gc != "Z"
   * @library /vmTestbase /test/hotspot/jtreg/vmTestbase
   *          /test/lib
   * @run driver jdk.test.lib.FileInstaller . .
   * @build nsk.jdwp.ReferenceType.Instances.instances001.instances001
   * @run main/othervm/native PropertyResolvingWrapper
*** 154,163 ****
--- 155,168 ----
  
          String testClassName = nsk.jdwp.ReferenceType.Instances.instances001.TestClass.class.getName();
  
          long typeID = debuggee.getReferenceTypeID(createTypeSignature(testClassName));
  
+         // Note! This test is broken, in the sense that it incorrectly assumes
+         // that no GC can happen before it walks the heap. In practice, it seems
+         // to only affect this test when using ZGC. However, this test will also
+         // fail when using other GCs if an explicit GC is done here.
  
          // create command with maxInstances=1, only 1 instance should be returned
          testClass(typeID, 1, 1, false, 0);
          // create command with maxInstances=0, all instances should be returned
          testClass(typeID, 0, expectedInstances, false, 0);