IBM has released the finished version of JSR-291, Dynamic Component Support for Java SE in the Java Community Process. According to the spec,
The Framework forms the core of the OSGi Service Platform Specifications. It provides a general-purpose, secure, and managed Java framework that supports the deployment of extensible and downloadable applications known as bundles.
OSGi-compliant devices can download and install OSGi bundles, and remove them when they are no longer required. The Framework manages the installation and update of bundles in an OSGi environment in a dynamic and scalable fashion. To achieve this, it manages the dependencies between bundles and services in detail.
It provides the bundle developer with the resources necessary to take advan- tage of Java’s platform independence and dynamic code-loading capability in order to easily develop services for small-memory devices that can be deployed on a large scale.
The functionality of the Framework is divided in the following layers:
- Security Layer
- Module Layer
- Life Cycle Layer
- Service Layer
- Actual Services