If you find that your Java programs are starting to use too much memory, there are methods available that can help you diagnose how much memory is allocated. The freeMemory() method in the Runtime class tells you approximately how many bytes are available, while the totalMemory() method tells you the total amount of memory available to the virtual machine:

 Runtime rt = Runtime.getRuntime();System.out.println("Total memory allocated to VM: " + rt.totalMemory());System.out.println("Memory currently available: " + rt.freeMemory());

These methods return integer values representing the number of bytes available. Although these methods don’t provide any detailed information on when or how the memory was allocated, you can locate problem areas by placing calls to freeMemory() at strategic locations within your code.