Finding source of a Gradle task

I am working with a giant codebase that is built and run using Gradle, a tool with which I personally am not particularly familiar. Nonetheless, there is a java main in the project that needs to be run fairly often in regular development, but whose classpath is miles long and whose arguments are esoteric and difficult to remember. I would like to roll the execution of this particular main into a Gradle task, which is the way that most of the other mains we need are run. However, I have no idea how to do this, and I can't seem to find the source for any of the other tasks we have. I had thought that after running

gradle tasks | grep -A<some-reasonable-number-of-lines> 'Application'

and then git greping for the task names that popped up, I would be able to find the source for our other tasks and simply emulate that. But the tasks named by gradle tasks don't actually seem to exist anywhere aside from the output of that command. In a project with more build.gradles than I can count, I am lost as to how to go about finding the source for a particular task. Advice?