It's quite possible to create responsive Java desktop apps. It's just that it takes an experienced Swing developer who has learned all the hard lessons about building that type of app.

That said, yes, many Java developers write bad code, but so do developers who write in other languages. Java just gets a higher profile because unfortunately the Java community has a tradition of writing libraries and APIs that sacrifice usability for flexibility (that's the kindest way I can put it, anyway).

Slightly off-topic: Am I the only one who feels that Eclipse is the IDE equivalent of a hair shirt? I find its UI sluggish, its insistence on imposing its ideas about project management on you irritating, and to be generally overcomplicated. To me, NetBeans, former versions of IntelliJ, and VS are much nicer products (mind you, half the time I still just use an text editor though).