Thread dumps
On This Lesson 4 topics
This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.
In this lesson
capture and read dumps for blocked or starved threads.
Planned topics
- Capture:
jcmd <pid> Thread.print(orjstack); take 3 dumps a few seconds apart. - Each thread shows state, stack, locks held and waited for.
- Many threads BLOCKED on one monitor means lock contention; the owner is named.
- Pool threads all parked and a queue growing means starvation.
- Dumps flag deadlocks explicitly.
Draft outline details
Demonstration
"http-nio-8080-exec-17" BLOCKED on <0x...> owned by "exec-3".
Check your understanding
Why take several dumps?
Show answer
One shows a moment; repeats show what is stuck versus moving.
Practice
Apply this lesson with the module's lab, exercises and quiz.
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