Java char to byte casting

Question

I have been testing the char casting and I went through this:

public class Test {     public static void main(String a[]) {         final byte b1 = 1;         byte b2 = 1;         char c = 2;          c = b1; // 1- Working fine         c = b2; // 2 -Compilation error     } } 

Can anyone explain why it's working fine in 1 when I added a final to the byte?

Answer 1

When the variable is final, the compiler automatically inlines its value which is 1. This value is representable as a char, i.e.:

c = b1; 

is equivalent to

c = 1; 

In fact, according to this section on final variables, b1 is treated as a constant:

A variable of primitive type or type String, that is final and initialized with a compile-time constant expression (§15.28), is called a constant variable.