KnowBench is a semantic user interface integrated into the Eclipse IDE that supports software developers during the software development process. It assists with identifying, acquiring, developing, distributing, preserving, and using knowledge through components like a semantic search engine, global metadata store, software development semantic wiki, and ability to manually or semi-automatically annotate source code semantically. Evaluations of KnowBench with software developers found that it achieved good scores in supporting knowledge acquisition, development, sharing, usage, and preservation. Semantic web technologies in KnowBench help better manage knowledge in software development activities.