How to Profile JVM memory in the code?

Question

I am writing a servlet that I can\'t test in Eclipse, I need to run on server. I want to do memory profiling and pinpoint any leaks. So, I think I need write debug statement

Answer 1

So, I think I need write debug statements that can tell me current memory usage.

I think you are like me who prefers to profile in code instead of using an external profiling tool like JVisualVM or JConsole.

You can use a tool called MemorySampler (written by me) from CoralBits that will tell you exactly in what line of your code memory is being allocated. Below an example:

ConcurrentLinkedQueue queue = new ConcurrentLinkedQueue();
MemorySampler.start();
for(int i = 0; i < strings.length; i++) queue.offer(strings[i]);
for(int i = 0; i < strings.length; i++) queue.poll();
MemorySampler.end();
if (MemorySampler.wasMemoryAllocated()) MemorySampler.printSituation();

Gives you the following output:

Memory allocated on last pass: 24576
Memory allocated total: 24576

Stack Trace:
    java.util.concurrent.ConcurrentLinkedQueue.offer(ConcurrentLinkedQueue.java:327)
    TestGC.main(TestGC2.java:25)

Now if you go to line 327 of the ConcurrentLinkedQueue source code, you will see that it allocates a Node instance there.

Disclaimer: I am one of the developers of CoralBits.