Go to Window → Preferences → Java → Editor → Content Assist.
In the column “Auto activation triggers for Java”, enter this:
.qwertyuioplkjhgfdsazxcvbnm_QWERTYUIOPLKJHGFDSAZXCVBNM
Add any other keys you want. You’re done. That answers your first query.
As far as second one goes, I think it already exists.