How To Submit
Download the starter files from the submit server. Then in Eclipse, right-click on your project root, choose Import, then Archive, then find the starter files you downloaded. Then import everything from the archive except the META-INF folder.
You can submit from Eclipse using the submit plugin. Once you've installed it, make sure you have the .submit file from the starter files in your project root directory. Then just right-click your project, Properties, Course Project Management, check enable. When you want to submit, right-click the project and choose Submit. You may get a weird message on your first submit, but it should work.
You can also submit via the web; select your .java files and the .submit, .classpath, and .project files, right click and say Export, then Java Jar File, make sure you're exporting all the code you wrote and nothing more, then save it to your hard drive. Then on the main submit server page, click submit under project 2 and give it the .jar file you saved.
You can also submit from the command-line using the same .submit file; grab the submit.jar from the public directory on GRACE.
Your code will be run from the public static void main(String[]) method of the Main class in the default package. It will read in its input from stdin and write its output to stdout.
You can see exactly how your code will be tested by examining the public tests.