Java 字符到字节转换

Question

我一直在测试字符转换，我经历了这个:

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
    }
}

谁能解释为什么当我向字节添加一个final时它在1中工作正常？

Answer 1

当变量为final时，编译器自动内联其值为1。该值可以表示为char，即:

c = b1;

等价于

c = 1;

其实根据this section on final variables , b1 被视为常量:

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.