1-Creational Patterns
These design patterns provides way to create objects while hiding the creation logic, rather than instantiating objects directly using new operator. This gives program more flexibility in deciding which objects need to be created for a given use case.

Abstract Factory Sets of methods to make various objects.
Builder Make and return one object various ways.
Factory Method Methods to make and return components of one object various ways.
Prototype Make new objects by cloning the objects which you set as prototypes.
Singleton A class distributes the only instance of itself.

2-Structural Patterns
These design patterns concern class and object composition. Concept of inheritance is used to compose interfaces and define ways to compose objects to obtain new functionalities.

Adapter A class extends another class, takes in an object, and makes the taken object behave like the extended class.
Bridge An abstraction and implementation are in different class hierarchies.
Composite Assemble groups of objects with the same signature.
Decorator One class takes in another class, both of which extend the same abstract class, and adds functionality.
Facade One class has a method that performs a complex process calling several other classes.
Flyweight The reusable and variable parts of a class are broken into two classes to save resources.
Proxy One class controls the creation of and access to objects in another class.

3-Behavioral Patterns
These design patterns are specifically concerned with communication between objects.

Chain Of Responsibility A method called in one class can move up a hierarchy to find an object that can properly execute the method.
Command An object encapsulates everything needed to execute a method in another object.
Interpreter Define a macro language and syntax, parsing input into objects which perform the correct opertaions.
Iterator One object can traverse the elements of another object.
Mediator An object distributes communication between two or more objects.
Memento One object stores another objects state.
Observer An object notifies other object(s) if it changes.
State An object appears to change its` class when the class it passes calls through to switches itself for a related class.
Strategy An object controls which of a family of methods is called. Each method is in its` own class that extends a common base class.
Template An abstract class defines various methods, and has one non-overridden method which calls the various methods.
Visitor One or more related classes have the same method, which calls a method specific for themselves in another class.

4-J2EE Patterns
These design patterns are specifically concerned with the presentation tier. These patterns are identified by Sun Java Center.

MVC Pattern Intercepting Filter pattern
Business Delegate Pattern Service Locator pattern
Composite Entity Pattern Transfer Object pattern
Data Access Object Pattern
Front Controller Pattern
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