I'm currently applying for an engineer role. The role is reasonably agnostic regarding specific skills which suits me well because I have a wide base and I like diversity, however they have said they are after more Java developers. Whilst I have programmed in Java and worked on Java projects I wouldn't claim any proficiency beyond amateur.

What sort of things should I really know about if the tech interview brings up Java questions? I'm not expecting them to but it would be foolish not to prepare for that eventuality.