Coberclipse is a eclipse plugin for Corbertura. It will instrument the classes during the build and show the code coverage after executing unit test cases.
BeCover is a Java code coverage tool based on source-code analysis. The main goal is to keep it small and fast, so using it as a plugin in the common IDE's can be achieved.
Tiria is a eclipse-plugin to view code coverage data (e.g. from cobertura) within the IDE. Main objective of the plugin is to show how the code coverage changes during project progress.