In running the test for 6376698 I have gotten this exception a few times:
Exception in thread "main" com.sun.jdi.ObjectCollectedException
at com.sun.tools.jdi.JDWPException.toJDIException(JDWPException.java:27)
at com.sun.tools.jdi.VirtualMachineImpl.instanceCounts(VirtualMachineImpl.java:510)
at InstanceCountsTest.getCounts(InstanceCountsTest.java:137)
at InstanceCountsTest.runTests(InstanceCountsTest.java:195)
at TestScaffold.startTests(TestScaffold.java:406)
at InstanceCountsTest.main(InstanceCountsTest.java:100)

This seems to occur after getting messages such as these:

[Full GC[Unloading class sun.reflect.GeneratedConstructorAccessor8]
[Unloading class sun.reflect.GeneratedConstructorAccessor13]
[Unloading class sun.reflect.GeneratedSerializationConstructorAccessor3]
[Unloading class sun.reflect.GeneratedConstructorAccessor24]
[Unloading class sun.reflect.GeneratedSerializationConstructorAccessor4]
[Unloading class sun.reflect.GeneratedConstructorAccessor3]