This package is now depreciated and unmaintained. It has been split into two separate, more focused packages.
The java-docs portion has been replaced by the more powerful javadoc-lookup. This one will fetch the documentation for you. It's also focused on supporting JVM-based languages more generally.
The java-mode-plus portion had been replaced by ant-project-mode. This is mostly a name change, with future changes focused more tightly on supporting Ant-based Java projects.
See the header comments in each file for full documentation. The recommended usage is in java-mode-plus.el.
To install drop these in your load-path somewhere and require them (after enabling ido-mode, if you use ido-mode),
(require 'java-mode-plus) (require 'java-docs)
To use java-docs you'll need to tell it where to find some documentation. For example,
The snippets directory contains some YASnippets that hook into java-docs class completing reads.