Welcome to the Java Ranch. While we pride ourselves on being friendly to those learning Java, we don't do homework. It would be best for your education if you attempted to do the application yourself. Do you know Java? If not, try going through the Java Tutorial. If you just need the details on the Java Comm API, check out the User's Guide. It may be in your benefit to search the Other Java APIs forum here, where questions about Java Comm are frequent. If you have specific questions, feel free to post the code you are having problems with and we will be glad to help. Since this is not an IO question, I'm moving it to Other Java APIs
The first thing to do is to download, install and test the COMM api package. DO NOT jump right into your project, run the samples that come with the package so that you are sure that the toolkit can find your serial and parallel ports.
The tricky bit that many people stumble on is getting the javax.comm.properties file in the right place so that it is picked up when java starts.