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.
If you mark the class implementing the interface as abstract, you only need to provide either partial, or default implementations of the method stubs defined in the interface. This type of class is typically called an Adapter. The remaining methods will then need to be implemented fully in a concrete subclass that inherits from this Adapter.
Be aware however, that by marking a class as abstract, you cannot instantiate it. You will have to instantiate a concrete subclass that has implementations of all of the methods defined by the interface.