OSGi, Open Services Gateway Initiative, defines an architecture to develop and deploy applications and modular libraries. & nbsp; OSGi container deployments such as Apache Felix and Equinox & nbsp; They allow you to divide your application into multiple modules and thus manage more easily the cross dependencies between them. & nbsp; OSGi containers are specifically intended for the development of complex Java applications that you want to divide into modules. & nbsp;

Here are some of the advantages it offers:

  • Install , uninstall, start and stop different modules of your application dynamically without restarting the container. & nbsp;
  • Having more than one version of a particular module running at the same time . & nbsp;
  • A very good infrastructure for developing service-oriented applications, as well as integrated, mobile and rich Internet applications.

The OSGi project was started by the OSGi Alliance in March 1999. Its main objective was to create an open specification for the delivery of managed services to local networks and devices. & nbsp; The basic idea is that once you add an OSGi service platform to a networked device, you can manage the lifecycle of the software components on that device from anywhere in the network. & nbsp; Software components can be installed, updated or deleted on the fly without having to interrupt the operation of the device. & nbsp;

In recent years, OSGi has emerged as a viable and valuable technology for business development. & nbsp;

In 2003, the Eclipse development team began looking for ways to make Eclipse a more dynamic rich client platform and increase the modularity of the tool. & nbsp; Eventually, the team decided to use the OSGi framework as a runtime component model. & nbsp;

Nearly all enterprise application servers support or plan to support OSGi . & nbsp; The Spring framework is also compatible with OSGi, through Spring Dynamic Modules for the project OSGi Service Platforms , which provides an infrastructure layer to facilitate the use of OSGi in the development of Java-based enterprise Java applications . & nbsp;

From the point of view of a business developer, the OSGi container has a space so low that you can easily embed it in a business application. For example, suppose you are developing a complex web application. & nbsp; You want to split the application into several modules: one module for the view layer, another for the DAO layer, and a third module for the data access layer. & nbsp; Using a built-in OSGi container to manage the cross dependencies of these modules would allow you to update your DAO layer (for example, from slow DAO to fast DAO) without restarting your application. & nbsp;

As long as your application complies with the OSGi specification, it should be able to run in any container compatible with OSGi. Currently, there are several popular open source OSGi containers, these are the two most commonly used: & nbsp;

  • & nbsp; Equinox , the reference implementation for the OSGi Service Platform framework portion.
  • & nbsp; Apache Felix , the OSGi container of open source of the Apache Software Foundation. & nbsp;