To be a real wrapper for an int, Integer should preserve the properties of an int. Since ints in Java are passed by value, they are effectively immutable as far as language semantics are concerned.

Typesafe enums offer a better alternative to Java's traditional enumerated types. Here's how to use typesafe enums correctly in your Java code.

Here's a quick tutorial on how to use printf to format Java int, long, short and byte values. It's pretty easy to do. And the output you can generate can be very visually appealing.