Books offer the best way to learn Java programming. On any programming topic you can find thousands of books. The only problem is that most of them are not cheap. Here are some free (and legal!) Java programming ebook resources I found useful.

One of the first free ebooks I read was Bruce Eckel’s Thinking in Java. This book was very good and helped me a lot in my career.

Do you know a good free ebook on Java? Please post them in the comments.

Free Java programming  ebook resources

Java tutorial by Sun - This is the best resource to start learning Java.

Thinking in Java, Thinking in C++ - Very good books by Bruce Eckel.

Introduction to programming in Java - A work in progress by David. J. Eck.

Data structures & design patterns in Java - Online html based book by Bruno.

Java design pattern companion - An excellent work by James W. Cooper.

Java data Structures - Download free ebook on Java data structures. Last update on 2002.

Java performance tips - Java performance tips by Peter sestoft.

1000 Java tips! - I haven’t read this yet, it sounds good

How to think like a computer scientist - A good computer science book based on Java.

Processing XML with Java - Online version of the huge book.

Securing Java - An online book dealing with Java security.

Java lanugage specification - An online book from Sun.