This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
checkstyle is great, but the eclipse compile has a number a valueable hints too. just make him pedantic by replacing every single "ignnore" with "warning" on the corresponding preference page (Java/Compiler/Errors)