What is an OSGi application?
OSGi defines a dynamic module system for Java™. The OSGi service platform has a layered architecture, and is designed to run on various standard Java profiles. OSGi Applications deployed to WebSphere® Application Server run on an Enterprise Java profile that is provided as part of the server runtime environment.
What is OSGi in WebSphere?
The OSGi Applications programming model in WebSphere® Application Server enables you to develop, assemble, and deploy modular applications that use Java™ EE and OSGi technologies. You can use tooling to deploy an enterprise application as an OSGi application that consists of one or more OSGi bundles.
How does OSGi framework work?
How does OSGi work? OSGi is a set of specifications that define a dynamic component system for Java. These specifications allow for a development model in which an application is composed of several components, and then packed into bundles. These components communicate locally and through the network via services.
What is OSGi the universal middleware?
The OSGi (Open Service Gateway Initiative) specification is a Java framework for developing and deploying modular software programs and libraries. The framework was originally managed by the OSGi Alliance, an open standards organization.
What are OSGi components?
As we discussed earlier, an OSGi component is the entity whose lifecycle will be managed by the OSGi container. To make a class act as component, we annotate it with @Component . We can start, stop and configure the component using Apache Felix Web Console.
Who uses OSGi?
Who uses OSGi? 11 companies reportedly use OSGi in their tech stacks, including Liferay, Business Filemanager, and SYSTHEMIS AG.
What are declarative services in OSGi?
OSGi declarative services are the OSGi way to handle the instantiation problem: the fact that we want to code to interfaces, but we need some way to instantiate classes and some way to provide some concrete instance of an interface in order for the parts of our modular application to work together.
What are OSGi services?
An OSGi service is a Java class or service interface, along with a number of service properties as name/value pairs. The service properties differentiate among different service providers that provide services with the same service interface.
Why do we need OSGi?
OSGi is a fast framework because it knows that which service will be loaded into OSGi environment thanks to pre-defined xml file. It reduces runtime cost thanks to lazy state. Service instance is created when they needed. Some bundle’s different version can be used by other bundle at the same time.
What is difference between OSGi bundle and Java package?
The key difference with OSGi is that a JAR is now all private, adding metadata in the manifest makes it a bundle that can safely share with other bundles. OSGi makes sure violations are detected ahead of time. So, can a bundle be used in place of a jar in a JavaEE application? yes, it is a normal JAR.
What is Apache Felix in AEM?
The Web console in AEM is based on the Apache Felix Web Management Console. Apache Felix is a community effort to implement the OSGi R4 Service Platform, which includes the OSGi framework and standard services. On the Web console any descriptions that mention default settings relate to Sling defaults.