Understanding Java Thread Dump

Question

Hi,
I was looking at the following thread dump
Full thread dump Java HotSpot(TM) Server VM (11.0-b16 mixed mode):
"pool-3-thread-1428" prio=10 tid=0x72b83800 nid=0x60ef waiting on condition [0x73318000..0x73318fb0]
java.lang.Thread.State: TIMED_WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x98983260> (a java.util.concurrent.SynchronousQueue$TransferStack)
at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198)
at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:424)
at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:323)
at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:874)
at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:945)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:619)
"MergeTask" daemon prio=10 tid=0x09454c00 nid=0x60e7 waiting for monitor entry [0x65106000..0x65106f30]
java.lang.Thread.State: BLOCKED (on object monitor)
at org.apache.log4j.Category.callAppenders(Category.java:201)
- waiting to lock <0x96d90bb8> (a org.apache.log4j.spi.RootLogger)
at org.apache.log4j.Category.forcedLog(Category.java:388)
at org.apache.log4j.Category.log(Category.java:853)
at sun.reflect.GeneratedMethodAccessor55.invoke(Unknown Source)
I can see that 0x98983260 and 0x96d90bb8 are memory addresses of condition object and lock object respectively (I hope ti. But I was puzzled with [0x73318000..0x73318fb0] and [0x65106000..0x65106f30].
What do these memory ranges indicate? Is there any documentation related to thread dump?
In OpenJDK source code I can see following comment. But I did not understand what it means.
// print guess for valid stack memory region (assume 4K pages); helps lock debugging
st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
Thanks,
Unmesh

Answer 1

Thread Dump Analysis On AIX Platform:
http://middlewaremagic.com/weblogic/?p=4348