Design patterns in java

Design patterns:

• Pattern means set of guide lines.
• Design patterns are solutions to commonly reoccurring problems in software development.
• Design patterns are well proven solutions to common software problems.
• Design patterns are best practices to use software technologies effectively in application development.  
• Design patterns used in analysis and requirement  phase of  SDLC.
• Design patterns can be implemented by using programming language.

Advantages:

• Reusable.
• These are already defined solutions to common re occurring problems so it reduces time.
• They are already defined so Easy to understand and debug.

Categorization:

• These are categorized into two parts.

1. Java SE Design patterns.
2. Java EE Design patterns.

Java SE Design patterns: 

•  In Java SE there are mainly three types.

1.Creational Design patterns:

1. Factory Pattern
2. Abstract Factory Pattern
3. Singleton Pattern
4. Prototype Pattern
5. Builder Pattern.

2.Structural Design patterns:

1. Adapter Pattern
2. Bridge Pattern
3. Composite Pattern
4. Decorator Pattern
5. Facade Pattern
6. Flyweight Pattern
7. Proxy Pattern

3.Behavioral Design patterns:

1. Chain Of Responsibility Pattern
2. Command Pattern
3. Interpreter Pattern
4. Iterator Pattern
5. Mediator Pattern
6. Memento Pattern
7. Observer Pattern
8. State Pattern
9. Strategy Pattern
10. Template Pattern
11. Visitor Pattern

Read More:
Factory pattern