Design Patterns in JDK

Design Pattern	Example in JDK	Description
Singleton	Runtime (hungry) NumberFormat
Factory	Integer.valueOf CLass.forName	Replace constructor Method name is more informative than constructor
Factory Method	Collection.oterator
Abstract Factory	java.sql UIManager
Builder	DocumentBuilder
Prototype	Object.clone Cloneable
Adapter	java.io.InputStreamReader(InputStream) java.io.OutputStreamWriter(OutputStream)
Bridge	Handler & Formatter in java.util.logging
Composite	javax.swing.JComponent#add
Decorator	java.io
Facade
Flyweight	String constant pool
Proxy	RMI
Iterator	Iterator
Observer	java.util.Observer, Observable Listener
Mediator	Swing ButtonGroup
Template method
Strategy
Chain of Responsibility	ClassLoader java.util.logging.Logger
Command	Runnable Callable ThreadPoolExecutor
Interpreter	java.util.regex.Pattern