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.
I did an online quiz on java earlier and I got to a question that asked when I should use interfaces and when to use abstract clases. I realize that I never thought much about this. Basically, I use instinct to decide when to use which. I don't really have a golden rule in regard to this principle. can anybody help?