There are two books we recommend to every developer: Effective Java: http://java.sun.com/docs/books/effective/ http://java.sun.com/docs/books/effective/ Java

There are two books we recommend to every developer: Effective Java: http://java.sun.com/docs/books/effective/ http://java.sun.com/docs/books/effective/ Java Concurrency in Practice: http://www.javapuzzlers.com/ http://www.javapuzzlers.com/ Everything else is covered by the excellent online documentation, including the language and VM specification books: http://docs.oracle.com/javase/specs/ http://docs.oracle.com/javase/specs/ Java Puzzlers (http://www.javapuzzlers.com/ http://www.javapuzzlers.com/) is a fun read that highlights many corner cases of the language and might be helpful for code reviews and debugging.