Java Precisely by Peter Sestoft

The third edition of Java Precisely provides a concise description of the Java programming language, version 8.0. It offers a quick reference for the reader who has already learned (or is learning) Java from a standard textbook and who wants to know the language in more detail. The book presents the entire Java programming language and essential parts of the class libraries: the collection classes, the input-output classes, the stream libraries and Java 8's facilities for parallel programming, and the functional interfaces used for that. Though written informally, the book describes the language in detail and offers many examples. For clarity, most of the general rules appear on left-hand pages with the relevant examples directly opposite on the right-hand pages. All examples are fragments of legal Java programs. The complete ready-to-run example programs are available on the book's website.