Why do these two statements show different result?

Question

Integer i1 = 127;
Integer i2 = 127;

// Statement 1 : true
System.out.println(i1 == i2);

i1 = 128;
i2 = 128;

// Statement 2 : false
System.out.println(i1 == i2);

https://code.sololearn.com/cqMfP6Czhd38/?ref=app