I would like to see design by contract become mainstream. JSR-305, Annotations for Software Defect Detection, is a step in the right direction. The applicability of this standard is broader than the name suggests. Here’s a talk about the JSR by Bill Pugh:http://video.google.com/videoplay?docid=-1531727105949862857
I would like to see compile-time and full IDE support for design by contact.