How to see which monitor is waiting for the stream?

I use netbeans and its profiler to view thread activity. The graphs show that when performing more than a workflow, threads can remain in several states: work, waiting, monitoring.
I wrote my Java application, so its worker threads should only use read-only variables without the need for synchronization.
However, when I run the netbeans profiler, I see that often my threads are in monitor state. I assume that they are waiting for the monitor to unlock, but I can imagine which monitor.

So my question is: is there a way to figure out which monitor is expecting a stream?

thank