Object pooling with valueOf()

We have all wrapped primitive int with wrapper Integer objects.

The regular way to achieve this would be to write:

Integer ONE = new Integer (1);

This would instantiate a new object each time as evidenced by the presence of the new operator. This repeated instantiation is wasteful most of the time.

We can do a one time instantiation of the object and pool the same object to re-use it when it is deemed required later. This may be done with the valueOf method.

Integer ONE = Integer.valueOf(1);

This may be compared to String instantiation by two different techniques:

String happy = "happy"; (pooling)
String happy = new String ("happy"); (non-pooling)