How to write java code in intention?

Hi,

I am still investgating how to write a importer to parse a existing XML format file and create a AST tree.

Right now I think the best solution is to write a intention in the root concept, using intension menu to trigger this operation.

In intention's execute function, it should

1. Use FileChooser to popup a window to let user select a XML file.

2. Parse the XML file, create node of root concept and all the children nodes. The newly created root node should replace existing one.

My question is, how to enable java and start to write java code? What language/module should I import?

At least I need FileChooser, File, and XML library to do the job.

Please someone give me some suggestions or a project for reference.

Thanks.