The JavaCore plugin was designed to act as a central location for the management of classpaths and sourcepaths that may be used by other Java-centric plugins. It uses jEdit 4.2's services API to tie together plugins providing classpath/sourcepath information and those using it. Neither need be aware of the other. This allows the user to select the service most useful to their style of work. A default service is included.
The plugins currently based on JavaCore (dotcomplete and codeaid) are no longer maintained. The recommended plugins for classpath management and completion in jEdit 4.3 and JDK 1.5 are ProjectViewer and JavaSideKick.