How to see what monitor is a thread waiting for via API?

Question

We have a junit test runner which timeout if one test is hanging. Now I want create a thread dump via API.

I know I can request the stacktraces via Thread.getAllStackTraces(). But the thread dump on the console include many more information like the monitor which a thread is waiting.

Are there an API to request the monitor on which a thread is waiting?

It's unclear to me - do you want to do it programmatically or manually? — Grzegorz Oledzki, May 17 '11 at 12:46
if you generate all the stack traces won't you see where a thread is waiting? — nsfyn55, May 17 '11 at 12:53
I think API is clear. I want do it programmatically. I want write the dump in the logs from test server if a timeout occur. The test server should not freeze that it terminate. That manually is not possible. — Horcrux7, May 17 '11 at 13:19
that's fine. Definitely API = programmatically. I just wasn't sure if we are on the same page. — Grzegorz Oledzki, May 17 '11 at 22:38

score 3 · Accepted Answer · edited May 23 '17 at 11:47

3

You could use JMX to create a thread dump.

See How do I create a thread dump via JMX? for an example. The ThreadInfo class supports getting the locked monitors.

edited May 23 '17 at 11:47

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answered May 17 '11 at 12:44

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score 1 · Answer 2 · answered May 17 '11 at 12:52

JDK 6 documentation contains a section on programmatic monitoring of the JVM MBeans . I have never used them and would not be able to provide you sample code but it will definately give you a start.

Managing and monitoring programmatic way

The Attach API to connect to a remote JVM

I hope it helps , It will be very helpful if you can share the outcome of your research.

How to see what monitor is a thread waiting for via API?

2 Answers2