Why does changing the returned variable in a final

Question

I have a simple Java class as shown below:

public class Test {

    private String s;

    public String foo() {
        try {
            s = "dev";
            return s;
        } 
        finally {
            s = "override variable s";
            System.out.println("Entry in finally Block");  
        }
    }

    public static void main(String[] xyz) {
        Test obj = new Test();
        System.out.println(obj.foo());
    }
}

And the output of this code is this:

Entry in finally Block
dev  

Why is s not overridden in the finally block, yet control printed output?

Answer 1

There are 2 things noteworthy here:

• Strings are immutable. When you set s to "override variable s", you set s to refer to the inlined String, not altering the inherent char buffer of the s object to change to "override variable s".
• You put a reference to the s on the stack to return to the calling code. Afterwards (when the finally block runs), altering the reference should not do anything for the return value already on the stack.