1 Introduction JDK 1.5 introduces several extensions to the Java programming language. One of theseis the introduction of generics. This tutorial is aimed at introducing you to generics. You may be familiar with similar constructs from other languages, most notably C++ templates. If so, you’ll soonsee that there are both similarities and important differences. If you are not familiarwith look-a-alike constructs from elsewhere, all the better; you can start afresh, withoutunlearning any misconceptions. Generics allow you to abstract over types. The most common examples are con- tainer types, such as those in the Collection hierarchy. Here is a typical usage of that sort: