Edge cases: NullPointerException
Of all possible edge cases, the null variable one, where an object has not been set, is the one that tends to sneak up
on programmers the most. It can arise for many reasons: someone forgot to initialize a variable, an object did not form
properly, someone filled in a website form incorrectly, … The list goes on and on.
In Java, when a method is called on a null variable, a NullPointerException is thrown.
In this exercise, try to trigger a NullPointerException in the given code.
This exercise is part of the course
Introduction to Testing in Java
Exercise instructions
- Call a method on
namethat will result in aNullPointerExceptionbeing thrown.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
public class NullPointer {
private static String name;
public static void main(String[] args) {
// Call a method on name that will throw a NullPointerException
System.out.println("My name has " + name.____ + " characters.");
}
}