Most of these files were made around 1998 until maybe 2001 or so, and reflect Java of that time. They were intended for a follow-up to a book published in 1997, but that never was. Today it is more of an example for instructional use and illustrates Java simply enough at that time. It was also before e.g. generics were implemented, when they still were experimental.
If you want to use this in any way, it is free to change/expand on or whatever you want to it. I contrast to the copyrights usually adopted to books.
It starts with a synopsis of the planned book, or an introduction to Java. Just to get things started.
A chapter on object orientation in Java. It outlines the traditional way of OO when describing a programming language. In short, what the language can do and is intended to do.
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Some files published in the Swedish computer magazine DMZ ('Datormagazin'). The archive does not seems to be coherent, and lacking files.