Memory management in Java

Java memory model is divided between Thread Stacks (One for each thread) and a heap area.

Thread Stack

It is a thread specific memory area and contains local variables, methods call information etc. JVM stacks could be of fixed size or variable size. If computation in a thread exceeds its stack size limit then JVM throws StackOverflowError and exits.


It contains all the objects created during application lifecycle. The heap is created when the virtual machine starts up. Garbage collector reclaims heap storage for objects and objects are never explicitly deallocated. The JVM is not using any automatic storage management system, and it may vary as per the system requirements. The heap may be of a fixed size or may vary as per requirement. The memory for the heap does not need to be contiguous.

Static variables are stored on heap area and object stored on the heap can be referred by references stored in thread stack.

Local variables are stored on stack area.

Updated on: 24-Feb-2020


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