What is Java Portlet and its characteristics

In this article we will see what is portlet, what is Java Portlet and its characteristics.

Contents

Portlet is a web component. Combine with other portlets, they form a complete comprehensive web page.
In simple term, we can say that a portlet is an independent web application. Which is used to render some portion of complete web page.
Just like other web applications, it takes request (HTTP or HTTPS) and generates response.
Content rendered by Portlet is just part of whole page.
Many portlets together form a complete web page. This way multiple functionality are available on one page. Thus how a Portal is developed.

Following two Java Specification Request (JSR) defined for Java Portlet.
- JSR-168 ( or Portlet 1.0 Specification )
  - This specification was defined to show aggregate content of multiple component on page.
- JSR-286 ( or Portlet 2.0 Specification )
  - This specification was added on top of JSR-168 with additional features.
  - Key features to this specification are as below
    - Inter Portlet Communication (IPC)
    - Ajax support
    - Serving resource like images, pdf etc.
    - Allow changing header like cookies, meta tags etc
    - Annotation support
    - Improved web framework integration
    - Portlet managed modes
  - Its super set of JSR-168.
These specification describes life cycle and characteristics of portlets.
To know more about the Portlet specification, refer following links
- Portlet Specification-Part 1
- Portlet Specification-Part 2

Portability :-
- Just like Servlet, Java Portlet written based on these specification can be deployed and executed on any compatible Portlet container. Thus Java Portlets are portable across portal containers.
Maintenance :-
- The underlying Java Portlet API and architecture will not change across the compatible portlet container.
Easy to Learn :-
- Java Portal API is available as a part of JSR Docs, and it will be consistent across portal container.