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.
"debug" has no special meaning and will be handled in whatever manner the servlet was coded to handle it. Without the servlet code, no one can say. And unless the servlet or your web app is configured to handle exceptions in whatever fashion you deem appropriate, they will be displayed.