COMP 202 Lecture Notes - Lecture 32: Exception Handling, Hard Disk Drive

• School: McGill University
• Department: Computer Science (Sci)
• Course: COMP 202
• Professor: Melanie Lyman- Abramovitch

Document Summary

Exceptions are some event that happens during the execution of the program that disrupts the normal flow of instructions. This happens when you ask the computer to do something that doesn"t make sense. Eg, dividing by 0 or accessing a value in an array at an index that doesn"t exist. In order to prevent our code from crashing at runtime, instead of using if statements/blocks to catch all the possible things to go wrong and have a condition for each, you can use these try-catch block s. You can have as many catch block s as you want. This makes sense to do if you want to do something different depending on what kind of exception happens. If you get a nullpointerexception, you might want to do something different than if you get an arithmeticexception. It will always happen when the try block exits. You can have a finally with just a try -- you don"t need a catch in-between.