Integer a = 127;
Integer b = 127;
System.out.println(a==b); // true
// but
Integer a = 128;
Integer b = 128;
System.out.println(a==b); // false
Integer b = 127;
System.out.println(a==b); // true
// but
Integer a = 128;
Integer b = 128;
System.out.println(a==b); // false
Java