Thread Dumps
The ThreadDump class offers a programmatic way to print a thread dump. It's not recommended for production code but can be handy in tracking down unexpected behaviour interactively. Using ThreadDump.dumpThreads(System.out), for example, would yield something like the following (formatting inspired by jstack).
Thread Reference Handler@2: (state = WAITING)
- java.lang.Object.wait(Native Method)
- java.lang.Object.wait(Object.java:474)
- java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
Thread main@1: (state = RUNNABLE)
- java.lang.Thread.dumpThreads(Native Method)
- java.lang.Thread.getAllStackTraces(Thread.java:1460)
- com.google.code.tempusfugit.concurrency.ThreadDump.dumpThreads(ThreadDump.java:25)
...
- com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:118)
- com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:40)
Thread Signal Dispatcher@4: (state = RUNNABLE)
Thread Finalizer@3: (state = WAITING)
- java.lang.Object.wait(Native Method)
- java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:120)
- java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:136)
- java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)
The dumpThreads method will also detect any Java-level deadlocks, see the next section for details.