Classes, fields, methods, constructors, and objects are the building blocks of object-based Java applications. This Java tutorial teaches you how to declare classes, describe attributes via fields ...

Intro to Java Interfaces An interface is a reference type in Java. Interfaces are a completely abstract type that is used to specify a behavior that classes must implement.

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