The Groovy debugger allows you to step thorough source code using the standard Step Over, Step Into, Step Out, and Drop Frame commands available in the Java debugger.
The debugger provides a variety of tool windows, including a stack frame and variables view:
The debugger also provides a watch and console view:
Code fragment evaluation is also available:
When debugging Groovy code, it can be helpful to set the IDE to not step into Groovy language classes. You can do this through the Settings->Debugger->Stepping Dialog. Add groovy.* and org.codehaus.groovy* as patterns for classes to skip: