JAVA...
The
JFC Swing Tutorial Second Edition

The JFC
Swing Tutorial Second Edition is a tutorial on creating
a GUI with JFC/Swing. It covers topics Getting Started
with Swing, Learning Swing by Example, Using Swing
Components, Laying Out Components Within a Container
and Writing Event Listeners.
The
Java Tutorial Continued 
The Java Tutorial Continued
is an online book which covers topics like IDL, Internationalization,
2D Graphics, Security in 1.2, Sound, JDBC Database
Access, RMI and Reflection.
The
Java Language Specification Third Edition 
The book provides complete,
accurate, and detailed coverage of the Java programming
language. It provides full coverage of all new features
added in since the previous edition including generics,
annotations, asserts, autoboxing, enums, for each
loops, variable arity methods and static import clauses.
The
Design Patterns Java Companion
This Java design patterns
book by James W. Cooper includes topics like Creational
Patterns, The Java Foundation Classes, Structural
Patterns and Behavioral Patterns.
Securing
Java 
Online version of Securing Java includes topics like
Mobile Code and Security: Why Java Security is Important,
Malicious Applets: Avoiding the Common Nuisances,
Java Security Guidelines: Developing and Using Java
More Securely and The Future of Java Security: Challenges
Facing Mobile Code.