Exercises: Exceptions

To get started, open up java-web-dev-projects on your machine. The starter code is in the exercises package inside org.launchcode.

Divide By Zero!

The professor you IA for, Professor Jackson, shared with you the code she uses to auto-grade students’ work. She and the other IAs have encountered some problems with the code in the past when they enter the total possible point value for an assignment. Occasionally, they accidentally enter 0 for the total number of possible points and the program encounters a fatal error when trying to divide by 0.

To help out with this issue, complete a method called Divide() in Main. The Divide() method takes in two parameters: x and y.

Your method should return the result of x/y.

However, if y is zero, you should throw an exception. Try to use an ArithmeticException and put your try/catch block in Divide() to test out your error-handling skills. If an exception is caught, make sure to print out a helpful message.

Test Student Labs

After mentioning to Professor Jackson that you would like to get some more practice with exceptions, she offered to let you write some grading software! Before she gives you full control over auto-grading students’ work, she asked if you could write a method called CheckFileExtension(). The CheckFileExtension() method takes in one parameter: fileName.

CheckFileExtension() should return an integer representing the number of points a student receives for properly submitting a file in Java. If a student’s submitted file ends in .java, they get 1 point. If a student’s submitted file doesn’t end in .java, they get 0 points. If the file submitted is null or an empty string, an exception should be thrown and you should give the student -1 points. What kind of exception is up to you, including to a custom exception!

In Main(), Professor Jackson has provided a hashmap of students and the names of their submitted files for you to test out your work. If an exception is caught, make sure to print out the error message.