Thread states in VisualVM profiler

VisualVM uses following states to indicate thread activity status:

• Running; 
• Sleeping; 
• Wait; 
• Monitor. 

 

What do these states mean?

Running.

Thread.State = RUNNABLE.

"Thread state for a runnable thread. A thread in the runnable state is executing in the Java virtual machine but it may be waiting for other resources from the operating system such as processor."

Sleeping

Thread.State = TIMED_WAITING.

 Thread state for a waiting thread with a specified waiting time. A thread is in the timed waiting state due to calling one of the following methods with a specified positive waiting time:

• Thread.sleep
• Object.wait with timeout
• Thread.join with timeout
• LockSupport.parkNanos
• LockSupport.parkUntil

Wait


Thread.State = WAITING.

Thread state for a waiting thread. A thread is in the waiting state due to calling one of the following methods:

• Object.wait with no timeout
• Thread.join with no timeout
• LockSupport.park

A thread in the waiting state is waiting for another thread to perform a particular action. For example, a thread that has called Object.wait() on an object is waiting for another thread to call Object.notify() or Object.notifyAll() on that object. A thread that has called Thread.join() is waiting for a specified thread to terminate.

Monitor

Thread.State = BLOCKED.

Thread state for a thread blocked waiting for a monitor lock. A thread in the blocked state is waiting for a monitor lock to enter a synchronized block/method or reenter a synchronized block/method after calling Object.wait.