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Java Guru's Collection
Java in a Nutshell: A Desktop Quick Reference (In a Nutshell (O'Reilly))Java in a Nutshell: A Desktop Quick Reference (In a Nutshell (O'Reilly)) by David Flanagan
Buy new: £19.79 / Used from: £15.96
A reference book for Java.
Effective Java (Java Series)Effective Java (Java Series) by Joshua Bloch
Buy used from: £3.93
Improve your Java coding skills with this one.
Expert One-on-one J2EE Design and Development (Programmer to Programmer)Expert One-on-one J2EE Design and Development (Programmer to Programmer) by Rod Johnson
Buy new: £24.87 / Used from: £29.50
If you are serious about Java design, then this is a must read.
Core J2EE Patterns: Best Practices and Design StrategiesCore J2EE Patterns: Best Practices and Design Strategies by Deepak Alur
Buy new: £24.14 / Used from: £16.00
The reference to J2EE design patterns is a must read for everybody.
Concurrent Programming in Java: Design Principles and PatternsConcurrent Programming in Java: Design Principles and Patterns by Doug Lea
Buy new: £23.64 / Used from: £10.50
This book is excellent only those who really want to get indepth knowledge of threading. Not recommened for beginners.
Java 1.5 Tiger: A Developer's NotebookJava 1.5 Tiger: A Developer's Notebook by Brett McLaughlin
Buy new: £19.54 / Used from: £2.33
For anyone who wants to quickly move on to Java 5.
Hibernate in Action: Practical Object/Relational MappingHibernate in Action: Practical Object/Relational Mapping by Christian Bauer
Buy used from: £11.01
The best book on hibernate. Explains a difficult topic in an easy manner.