Hi,
What are possible scenarios/use case where scripting language like ruby, Jython etc are used along with Java?

Thanks,
Badrish

One use case is for allowing extensions or plugins to be written for your app using a scripting language.

Another would be to allow for writing complex filters or formulas for an application. Say you had a task management app and you wanted to allow users to write a filter so that they can create their own views on the data. Yes, you could give them some subset of SQL, but giving them access to a scripting language would be a bit more safe.
Another example of this would be in a scientific app where complex algorithms or equations may need to be created by the user and then used in the application... without having to recompile.

Hope this helps.