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.
X stands for eXtension. Any "X" parameter is vendor-specific, and unlike the other options isn't guaranteed to be available on all JVM implementations - for example, IBM's jikes or the open-source IcedTea VMs.
Customer surveys are for companies who didn't pay proper attention to begin with.