I have produced a book called Understanding Java.
Here is a link to the WWW pages associated with my book on Java.
I'm written a number of papers
about Java, PHP, XML, C#, .NET and Web Services.
Here are some links to these papers.
Linux Desktops at Oxford
OOP using VB.NET
Java 5 catches up with C#
C# is not just Java: these notes are only available to members of the Universities of Durham and Oxford
Web Services using .NET
Web Services using Axis
An Introduction to PHP
Processing XML using PHP
Processing XML using Java
From C++ to C#
Comparing .NET with Java
A Taste of C#: this paper gives an overview of C# for Java programmers
Java: some steps towards good quality code
Design of Classes
Teaching a Course on Understanding Java
A Taste of Java: this paper gives an overview of Java
Getting Started with Java
Developing Distributed Systems with Java
Using CORBA and JDBC to produce Three Tier Systems
Java Development Tools
Java versus C++
Resources about Java