I'm seeing a crash when using java.lang.instrument to (dummy) redefine java.lang.Object and later call clone(). Triggering a Full GC provokes this problem much quicker.

I have attached a small reproducer (Agent.java) - an instrumentation agent that redefines java.lang.Object without actually modifying the byte code. It then calls clone in a tight loop together with System.gc() to do some Full GCs.

Reproduce like so:

1. javac Agent.java
2. jar cmf MANIFEST.MF agent.jar Agent.class
3. java -javaagent:agent.jar Agent
4. Wait a millisecond or two

I can *not* reproduce on older releases, nor with 7u12-b05 so it's likely that this is a newly introduced regression in jdk8.