I need a way to request a heap dump from within the application.
Rationale: When I encounter a specific error condition, I'd like to dump heap, so that I can see what is holding on to the memory.
But I would like to automate this (For example, when I detect that some specific condition has occurred. Or when a watchdog doesn't gets its pings anymore. When some test fails). Thus I need a way to dump the heap from within the application itself. I can't seem to find it with the MX beans stuff. Although the MX Beans can give very nice stack traces with monitor and "ownable synchronizer" info, deadlock and contention info, I can't seem to find a way to request a heap dump. Are there any such way? Or by some indirect means, for example how does these JVisualVM things do it? And one can tell the JVM to dump core on OutOfMemoryExceptions..?
If it's not enough to dump heap on OutOfMemoryError, there's a HotSpot-dependent way of programmatically dumping heap from Java applications, if that's OK.
What about using the VM option -XX:+HeapDumpOnOutOfMemoryError to tell the HotSpot VM to generate a heap dump when it runs out of memory?
来源：https://stackoverflow.com/questions/1818897/request-java-heap-dump-core-dump-from-within-application