When Notes 8 was released, it opened a whole new world of application development based on Eclipse technology.  The combination of the Eclipse plugin framework and the existing Notes.jar APIs enabled interesting and powerful plugins to be built on top of Lotus Notes.  Notes.jar APIs allowed plugin developers to access back-end information about Domino applications, but did not provide a means to access information about the Notes UI.  The information that could be obtained about the Notes UI was accessed through Eclipse APIs or through unsupported, undocumented Notes plugin APIs that were not intended for external use.  The Notes Client Java UI APIs were introduced in Notes 8.5.1 as a means for plugin developers to access information about the Notes UI through well documented and supported APIs.  In conjunction with Notes.jar APIs, the Notes Client Java UI APIs allow Eclipse plugin developers to create robust applications that leverage their Domino data in the Notes UI.