If you’ve read my Java 101 tutorial introducing static classes and inner classes, you should be familiar with the basics of working with nested classes in Java code. In this associated tip, I ...

Do you need to know how to sort Java objects in a collection, array, or map? Here's how to use the Comparable and Comparator interfaces and avoid ClassCastExceptions.

Before printing the ArrayList, ... However, the Java Platform provides a data structure that greatly simplifies the use of reference objects like this, called the java.util.WeakHashMap class.

But primitive types aren’t objects, and that presents a problem. For example, all the collection classes in the JDK hold data as objects. If a developer has a set of int values they want to store in ...