Returning a value from function

How does returning a value from a function internally works ?

See this example..

alt text

Can a function return any value?

If a function is defined as having a return type of void , it should not return a value. In C++, a function which is defined as having a return type of void , or is a constructor or destructor, must not return a value. If a function is defined as having a return type other than void , it should return a value.

What is function should return a value?

A function that returns a value is called a value-returning function. A function is value-returning if the return type is anything other than void . A value-returning function must return a value of that type (using a return statement), otherwise undefined behavior will result.

The JVM uses a value stack to hold values, and the stack is shared across all method calls on that thread. Normally, when a non-void method returns, the return value is pushed on the stack, and the caller pops it off the stack and either uses it or discards it.