Implement a database of courses and students for a school, keeping track of which students are taking which courses. Each course must be represented by a name (a String) and each student must be represented by a student id number (an Integer).

There are many ways you could do this, but since the purpose of this assignment is to get you to practice using the Collections Framework.

You have to represent each course as a Set of student id numbers. You must show the entire database as a Map from course names to these id number sets. In other words, your database must be a map from Strings to sets of Integers. When displaying the contents of the database, the courses must appear in alphabetical order and the id numbers inside a class must appear in numerical order. That could influence your choice of types from the Collections Framework.

• StudentDatabase.java: This is a skeleton version of the module you must write. It contains a "stub" for each of the required methods, plus a comment describing what that method must do. So I won't bother describing all the methods in this web page.

• DatabaseTest.java: An interactive testing program you can use to test your database class.