Java - Threads - Classes that Inherit Thread Class

**Thread Reference can have any of these objects.

ForkJoinWorkerThread Class java.lang.Thread 1.7 Link
InheritableThreadLocal Class java.lang.ThreadLocal 1.2 Link
Thread Class java.lang.Object 1.0 Link
Thread.State Class java.lang.Enum 1.5 Link
ThreadDeath Class java.lang.Error 1.0 Link
ThreadGroup Class java.lang.Object 1.0 Link
ThreadLocal Class java.lang.Object 1.2 Link