What?

Question

Whyyyyy? What's the logic of this?
https://code.sololearn.com/cgdsDC8guqfy/?ref=app

Answer 1

hi I am new here its my first post I wish this can solve your problem with this program 😅😅
we know that , if two references point to the same object, they are equal in terms of ==. If two references point to different objects, they are not equal in terms of == even though they have the same contents.

So, here last statement should be false as well.

This actually where it gets interesting, if you look into the Integer.java class , you will find that there is a inner private class, IntegerCache.java that caches all Integer objects between -128 and 127.

So thing is, all small integers are cached internally and when we declare something like –

Integer c = 100;

What it does internally is:

Integer i = Integer.valueOf(100);

Now if we look into the valueOf() method , we will see-

    public static Integer valueOf(int i)
{      
if (i >= IntegerCache.low && i          
return IntegerCache.cache[i + (-IntegerCache.low)];       return new Integer(i);     }

If the value in the range -128 to 127, it returns the instance from the cache.

So

Integer c = 100, d = 100;

basically point to the same object.

Thats why we do –

System.out.println(c == d);

We get true.