Why doesn't Java autoboxing extend to method invocations of methods of the autoboxed types?

Question

I want to convert a primitive to a string, and I tried:

myInt.toString();

This fails with the error:

int cannot be derefere         


        

Answer 1

The valid syntax closest to your example is

((Integer) myInt).toString();

When the compiler finishes, that's equivalent to

Integer.valueOf(myInt).toString();

However, this doesn't perform as well as the conventional usage, String.valueOf(myInt), because, except in special cases, it creates a new Integer instance, then immediately throws it away, resulting in more unnecessary garbage. (A small range of integers are cached, and access by an array access.) Perhaps language designers wanted to discourage this usage for performance reasons.

Edit: I'd appreciate it if the downvoter(s) would comment about why this is not helpful.