Design Patterns Interview Questions

• Explain GoF Design patterns .

1. Creational : defines  how the objects are created 
2. Structural : defines relationship between the classes
3. Behavioral : defines how objects communicate with each other 

• Explain Creational Design Patterns .

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

• Explain Structural Design Pattern .

1. Adapter : implementing class can work with incompatible interface.
2. Bridge : enables to implementing class and the interface to vary independently.
3. Composite : Composite lets client treat individual objects and compositions of objects uniformly.
4. Decorator
5. Facade
6. Flywheel
7. Proxy : a new object created to handle the operation.

• Explain Behavioral Design Pattern .

1. Chain of Responsibility
2. Command
3. Interpretor : how to include language  elements
4. Iterator
5. Mediator : simplify communication between objects
6. Observer : multiple objects notification
7. State : modify the behavior on state change
8. Template : abstract definition of algorithm
9. Visitor : add polymorphic functions to class noninvasively .

• Explain J2EE Patterns 

1. 
   

• Explain association in Java .

Association : has a relationship 

1. Composition : sub objects cannot exist without the parent object .
2. Aggregation : sub objects can exist without the parent object .

• Explain UML class diagram .