This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Yes it is possible. But it is recommended that you try not to have variables with same name in different scopes. If you do have such a case in which variable with the same name is present in lets say, page and session scopes then when the EL expression is used which requires rearching the various scopes then it will return the variable in the scope which was searched first ie. page.