How did you configure Emacs&CEDET so that it auto-completes the tags from the imported java-files? Did you use EDE, or a semanticdb-project-root? I ask because this is something I had working last Fall (completion of symbols both from Java source files, and also from JAR files), but I'm having trouble with it as I return to it.
How exactly are you invoking completions, by the way? Using Senator, which I think is older and less "intelligent"? Or using the Analyzer, which is newer and does a better job of finding the right symbols to complete (when it works)? When I use Senator, using something like senator-completion-menu-popup, I get a completion menu, but it's not accurate. When I try semantic-ia-complete-symbol-menu, I get nothing (`Cannot find types for ....').