In Java, nested classes are categorized as either static member classes or inner classes ... Instead, you can use an object initialization block ({}) as a constructor. Anonymous classes are ...

From a maintenance point of view, inexperienced Java developers may find the inner class difficult to understand. The use of inner classes will also increase the total number of classes in your code.

Starting with JDK 1.1, Java ... Inner classes may access static data but may not declare static members unless those members are compile time constants. Deciding which type of nested class to use ...