Java has many built-in exception classes, such as NullPointerException and IllegalArgumentException. At times however, you might want to create your own exception class. For example, as opposed to throwing IllegalArgumentException when a 0 is detected as a divisor during a division operation, you might wish to throw a DivideByZeroException. This exception class does not exist in the Java core API, but you can create one yourself. The seven steps below will show you how to create an exception class in Java.