How to make two programs communicate each other?

I work in a processors lab. We run tests on the processors. The PCs that run the testing software (third party software) are using Red Hat OS. We do the documentation in Microsoft Excel (in other PC). As Excel is not fully suits our needs, I would like to replace it with a software I'll write myself. I would like to code it in Java. As for now, I see one barrier, I don't know how to make my program communicate with the testing software so I would like to know how to accomplish that. I want to be able to load test programs from my program, terminate running tests and to collect the information regarding every processor test result. How can I achieve that?