Basically this is a hypertext reference for Java 2. It covers the 182 packages and 3900 classes that make up that version. Many people still prefer paper copy to electronic form and would naturally reach to their bookshelf when they want to check some detail (and with the size of Java, you will need to check details quite often) but there is no way that most airlines are going to allow you to carry on a laptop and the complete Java Class Library reference book. Mind you, you would get fairly fit carrying that lot around.

You get the point, if you need to work on Java away from you're your home/office you need a portable reference and this CD might be just what you are looking for. Please note that it is not a reference about the language, if you want information about the ranges for fundamental types, how to write an inner class etc. you will need something else.

For its intended audience this is a cost effective solution, though with the way Java has been growing you may need to replace it next year.