In Effective Java, Joshua Bloch does a great job describing best practices that you as developer will find useful on a daily basis. For example, I really found his description of the builder pattern (Item 2, page 11) quite interesting. Another Item that fascinated me, was Item 15 (page 73) - "Minimize mutability". Both items are part of a broader theme throughout the book that promotes creating code that is as immutable as possible. In that regard, reading the book will enable you to simply write better and safer code. The book also leads the way towards promoting functional programming techniques which will come in quite handily when developing multithreaded applications. Therefore, as a next book I may recommend reading Java Concurrency in Practice by Brian Goetz.