final variable case in switch statement

Question

        final int a = 1;
        final int b;
        b = 2;
        final int x = 0;

        switch (x) {
            case         


        

Answer 1

The final variable without value assigned to it is called a blank variable. A blank final can only be assigned once and must be unassigned when an assignment occurs or once in the program.

In order to do this, a Java compiler runs a flow analysis to ensure that, for every assignment to a blank final variable, the variable is definitely unassigned before the assignment; otherwise a compile-time error occurs

That is why when the compiler compiles the switch construct it is throwing constant expression required because the value of b is unknown to the compiler.