There are 2 ways in UI to execute some target before Run/Debug session. The first way is to make all necessary settings in Run configuration dialog. The second is to set flag Execute On on target in Ant build window AND set the flag Execute Ant Task in Run configuration dialog. It looks so: 1. Get any run configuration. 2. Add ant project to Ant Build window. 3. Set Execute Before Run/Debug on some target in this window. Run your configuration. See that ant target is not executed. 4. Go to Run configurations. See that flag Execute Ant Task is OFF. Set it ON. Run your configuration. Now ant runs. Why users have to perform step 4? Probably it can be done automatically.