Thanks to a lot of research and some answers found here. I have been able to use the javadoc command to generate some html files. My question is, once I have successfully generated these files, where do I place them (directory) so that they show up as javadoc when using my compiled jar library?
Most IDEs allow you to select a JAR and then set the folder or JAR which contains the javadoc in a properties dialog.
That said, javadoc is only useful when it was created with a lot of care. Most of the time, the sources are much more useful (especially since sources can't lie, they contain all the corner cases, people are used to read source code and most developers are very, very bad at writing documentation).
All IDEs I know (Eclipse, IDEA, Netbeans) can extract javadoc from a JAR which contains the sources at runtime.