What is the difference between stack and heap in Java? Where are strings stored?

In Java, the stack and heap are different memory areas with different purposes:

• Stack — this is the memory area where local variables of methods and function calls are stored. Each thread has its own stack. Access to data on the stack is very fast, and memory is allocated and freed automatically when entering and exiting methods.

• Heap — this is the memory area where objects and arrays created with the new operator are stored. Memory in the heap is managed by the garbage collector.

Where are strings stored?

Strings in Java are objects of the String class, so they are stored in the heap. There is a special string pool (String Pool) where string literals are stored for memory optimization. This pool is also located in the memory area associated with the heap (in modern JVMs, the string pool is part of the heap).

Example:

String s1 = "hello"; // string literal, stored in the string pool
String s2 = new String("hello"); // new object in the heap