runTest throws an Exception which is not a subtype of RunTimeException(those which extend are unchecked exception). Therefore TestException is known as a checked exception.
Since
test() runs the runTest method, a TextException a
checked exception is thrown inside the method. The jave rule is that checked exceptions should be caught or declared. Caught means the exception occur in a try catch block and is caught by catch. Declared means that the method must declare the exception in the throws clause of the method. In this case the exception is not caught therefore runTest must declare a throws TestException(or a type that is a super type).
unchecked exceptions do not have this restriction
exceptions in the java spec