Memory Profiling Java Application

In continuation to the last post on Jboss Profiler, thought of sharing this simple and elegant memory profiler that ships with your JSDK (jmap)...

• To know the # of instances & type of objects in the heap in a simple and quick way,

1. jmap -histo > snapshot1.txt
2. Sample Output:

num #instances #bytes class name
--------------------------------------
1: 5555 6013016 java.util.Hashmap
2: 103 482888 org.apache....
3: 2000 334928 org.jboss...
4: 1280 274976 org.spring...

• To troubleshoot a memory leak, do the above command multiple time and observe the snapshot.
• jconsole is good enough, but this give a verbose details on the memory.
• jhat is cool utility to browse the object topology over http on a specific port for analysis.