RSense is a tool for doing static analysis of Ruby source code. Rsense is used in conjunction with an editor plugin.
rsense-server is the communications bridge between the user (or editor plugins the user is using) and the rsense library written in java.
RSense is a tool for doing static analysis of Ruby source code. Rsense-core contains the "library" portion of rsense, as well as the stubs and other artefacts it needs to run.