I am trying to explore CQ5. I have two questions.
1) How can we define custom Extension Points in Adobe CQ5 ? (similar to what is done in Eclipse Plugin applications)
2) How to read the configuration done by contributors/extensions to the custom Extension point?
Or if anyone can help for an alternative way to expose a extension point.
I'd suggest you read http://www.osgi.org/wiki/uploads/Links/whiteboard.pdf which describes the pattern used for "extension points" throughout CQ and Sling.
1) By creating an interface.
2) By accessing the OSGi service registry either directly or through Declarative Services.