Hey Kalyani,
These are the links for Design Patterns posted by some rancher.
1)
http://corej2eepatterns.com/Patterns2ndEd/index.htm 2)
http://java.sun.com/blueprints/corej2eepatterns/Patterns/index.html These are the patterns you have to know for the exam.These are specified in Sun website.
* Given a scenario description with a list of issues, select a pattern that would solve the issues. The list of patterns you must know are: Intercepting Filter, Model-View-Controller, Front Controller, Service Locator, Business Delegate, and Transfer Object.
* Match design patterns with statements describing potential benefits that accrue from the use of the pattern, for any of the following patterns: Intercepting Filter, Model-View-Controller, Front Controller, Service Locator, Business Delegate, and Transfer Object.
Hope this information helps.