OSGI Lifecycle

OSGI Lifecycle

Since Liferay has adopted OSGI standards it is necessary for us to know basic's of OSGI.

OSGI-stands for  Open Services Gateway initiative.

OSGI is a Java framework for developing and deploying dynamic modular software applications. 

Basic OSGI Module Lifecycle

OSGI Lifecycle includes following states

1. Installed
2. Resolved
3. Starting
4. Active
5. Stopping
6. UnInstalled

Fig shows OSGI Module Lifecycle

1) Installed

The bundle has been installed into the OSGi container, but some required bundle dependencies is missing.A bundle in this state can’tbe start.

2) Resolved

When bundle is in resolved state means all the required 

dependencies is available.And bundle is ready to be started.

3) Starting

Bundle is being started and BundleActivator.start() method is 

executed.

Bundle with lazy activation policy stay in this state until one of 

class file is loaded.It is state between resolved and active.

4) Active 

The bundle is active and running.

5) Stopping

Bundle is being stopped & BundleActivator.stop() method is 

executed.After stopping state is complete it again enters in to resolved state,Once enter in resolved state it can again started.

6) UnInstalled

Bundle has been removed from osgi container.