Analyze Java Virtual Machine
Thread Dump
kill -3 <pid>
Creates a thread dump on linux.
jstack -l <pid>
also creates a thread dump on a running VM (and leaves it running).
Heap Dump
jmap -dump:format=b,file=dump.bin <pid>
Creates a dump to the file dump.bin of the passed process. The file is not human readable. Tools like MAT can help you analyze the dump.