What is the following code execution result?


Integer i1 = 10;
Integer i2 = 10;
           
Double d1 = 10d;
Double d2 = 10d;

System.out.println(i1 == i2);
System.out.println(d1 == d2);

true
false
true
true
false
false
false
true

Explanation

This is because of how java cache for auto-boxed integer values work. From Java Language Specification 5.1.7:

If the value p being boxed is an integer literal of type int between -128 and 127 inclusive (§3.10.1), or the boolean literal true or false (§3.10.3), or a character literal between '\u0000' and '\u007f' inclusive (§3.10.4), then let a and b be the results of any two boxing conversions of p. It is always the case that a == b.

And there is no such auto-boxing cache for Double class.