The Eclipse Plugin can be used to launch a Groovy Console or Groovy shell* from any Groovy or Java project. When the console is launched, you will have access to all classes on the project's build path.

This is an easy way to quickly test any Java or Groovy code and immediately view the output. The typical alternative would be to create a JUnit test, run the test, check the output, modify the code, run the test, check the output modify the code.... In any case, this is a lot easier because you can do it all without terminating the JVM.

Example Usage

You can use the Groovy Console from Eclipse to quickly inspect the functionality of your Java code, or even to inspect the output of a not-so-well-documented third-party library. This is particularly convenient because you don't have to create a JUnit test.

Say you want to test the FilenameUtils class...

Note that this is a plain Java project.
Right click on the project and select Groovy -> Groovy Shell

Test the classes in the Eclipse console:

Note that you still had to type the import ... statement. That is because, as in any Groovy script, you need an import or a fully qualified class name. The important thing here, is that all project libraries and code are immediately accessible in the Groovy shell.

The Groovy Swing-based console can be used as well, but since it takes significantly longer to load the GUI, it is often more convenient to run the command-line shell for simple tests.

Future Improvements

A future goal is to integrate the Groovy console with the Eclipse debugger. One could then dynamically exercise code from the console, then modify the code. Through the magic of Eclipse's hot code replace, the developer could 'work it' until it demonstrates the correct behavior – all in one invocation of the JVM.

Notes:

• The Groovy shell is the class name for the console that runs on the command line, without Java Swing widgets.