Couple of design patterns or architectural pattern most people know already

“Design patterns are recurring solutions to design problems.”

Patterns: According to commonly known practices, there are 23 design patterns in Java. These patterns are grouped under three heads:
1. Creational Patterns
2. Structural Patterns
3. Behavioral Patterns


Intercepting Filter : Facilitates preprocessing and post-processing of a request.

View Helper : Encapsulates logic that is not related to presentation formatting into Helper components. 

Business Delegate :Reduces coupling between presentation-tier clients and business services. It hides the underlying implementation details of the business service, such as lookup and access details of the EJB architecture.

Data Access Object : Abstracts and encapsulate all access to the data source. The DAO manages the connection with the data source to obtain and store data.

Factory Pattern : The factory method pattern is an object-oriented creational design pattern to implement the concept of factories and deals with the problem of creating objects (products) without specifying the exact class of object that will be created. Inheritance also a factory pattern.

The factory pattern can be used when:

• The creation of an object precludes its reuse without significant duplication of code.
• The creation of an object requires access to information or resources that should not be contained within the composing class.
• The lifetime management of the generated objects must be centralized to ensure a consistent behavior within the application.

Model–view–controller (MVC) is a software architecture pattern that separates the representation of information from the user's interaction with it.^[1][2] The model consists of application data, business rules, logic, and functions. A view can be any output representation of data, such as a chart or a diagram. Multiple views of the same data are possible, such as a pie chart for management and a tabular view for accountants. The controller mediates input, converting it to commands for the model or view.^[3] The central ideas behind MVC are code reusability and separation of concerns.^[4]

Reference : http://www.allappforum.com/j2ee_design_patterns/j2ee_design_patterns.htm