The change "8046282: SA update" introduced the following new code in agent/src/share/classes/sun/jvm/hotspot/oops/Klass.java + traceIDField = type.getField("_trace_id"); But I can not find the corresponding field in src/share/vm/oops/klass.hpp. The Klass class only contains the macro TRACE_DEFINE_KLASS_TRACE_ID which is defined to "typedef int ___IGNORED_hs_trace_type2" in traceMacros.hpp. This leads to an error when calling for example jstack on a core file: $ images/j2sdk-image/bin/jstack ./images/j2sdk-image/bin/java core Attaching to core core from executable ./images/j2sdk-image/bin/java, please wait... Debugger attached successfully. Server compiler detected. JVM version is 1.9.0-internal-d046063_2014_07_10_11_16-b00 Deadlock Detection: Exception in thread "main" java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:484) at sun.tools.jstack.JStack.runJStackTool(JStack.java:140) at sun.tools.jstack.JStack.main(JStack.java:106) Caused by: java.lang.ExceptionInInitializerError at sun.jvm.hotspot.oops.ObjectHeap.initialize(ObjectHeap.java:74) at sun.jvm.hotspot.oops.ObjectHeap.<init>(ObjectHeap.java:110) at sun.jvm.hotspot.runtime.VM.getObjectHeap(VM.java:582) at sun.jvm.hotspot.runtime.DeadlockDetector.print(DeadlockDetector.java:55) at sun.jvm.hotspot.runtime.DeadlockDetector.print(DeadlockDetector.java:39) at sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java:62) at sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java:45) at sun.jvm.hotspot.tools.JStack.run(JStack.java:66) at sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:260) at sun.jvm.hotspot.tools.Tool.start(Tool.java:223) at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118) at sun.jvm.hotspot.tools.JStack.main(JStack.java:92) ... 6 more Caused by: java.lang.RuntimeException: field "_trace_id" not found in type Klass at sun.jvm.hotspot.types.basic.BasicType.getField(BasicType.java:183) at sun.jvm.hotspot.types.basic.BasicType.getField(BasicType.java:190) at sun.jvm.hotspot.types.basic.BasicType.getField(BasicType.java:194) at sun.jvm.hotspot.oops.Klass.initialize(Klass.java:58) at sun.jvm.hotspot.oops.Klass.access$000(Klass.java:33) at sun.jvm.hotspot.oops.Klass$1.update(Klass.java:37) at sun.jvm.hotspot.runtime.VM.registerVMInitializedObserver(VM.java:394) at sun.jvm.hotspot.oops.Klass.<clinit>(Klass.java:35) ... 18 more Is this a problem with OpenJDK only (i.e. is '_trace_id' defined in Oracle proprietary builds) ?. Or is this another problem?