java primitive type cache

    public static void main(String[] args) {
        Integer a = 127;
        Integer b = 127;
        System.out.println("a==b："+(a==b));　　//a==b：true
        Integer c = new Integer(127);
        Integer d = new Integer(127);
        System.out.println("a==b："+(c==d));　　//a==b：false
        Integer e = 128 ;
        Integer f = 128;
        System.out.println("a==b："+(e==f));　　//a==b：false
    }

For Byte/Short/Long, it is similar to Integer, in the range of -128 to 127, there is a corresponding cache

To sum up, for the wrapper class corresponding to the above basic types, as long as it is within the cache range, that is, within the range of -128 to 127 (one byte, the range of complement representation),

We can directly use == to judge the equality.

float, double, boolean, char are not cached