The thing that makes java pleasant is large open source ecosystem around it + IDE quality (meaning mostly refactoring and code navigation, especially when compared to dynamic languages). Frameworks like spring or hibernate etc are mature enough and old enough, so there is a lot to learn just by reading.

The language itself makes it easier to figure out what large code written by somebody else was mean to do - not that everything would be readable nor anything like that, but easier then say ruby or javascript.