What are design patterns?

Design patterns represent the best practices used by experienced object-oriented software developers. Design patterns are solutions to general problems that software developers faced during software development. These solutions were obtained by trial and error by numerous software developers over quite a substantial period of time.

There are around 23 design patterns and they can be classified under 3 main categories as,

1. Creational Patterns
2. Structural Patterns
3. Behavioral Patterns