SpringSource Tool Suite TM (STS) is a free (not open source) set of developing tools for spring based applications, it is eclipse based (an eclipse distribution, but can also installed as plugins in your eclipse instance).
The Spring Tool Suite comes with a very cool feature for developing OSGi based applications, the STS adds a listener to your eclipse project resource and when something changed (saved) the effected bundle will be automatic restarted. This is very cool for developing OSGi based application. To activate the feature you must enable the „Spring Dynamic Modules OSGi Bundle Updater“ see the screenshot.
The Option can be found under the project setting of your bundle. After activating the Bundle Updater in the project setting, add the follow argument “-console ${osgi.console.port}” to the command line arguments of your launch configuration.
Links:
http://www.springsource.com/products/sts