Exception, RuntimeException

RuntimeException 을 상속받아 만든 클래스 ( 혹은 그 자신) 은 

의무적으로 catch 하지 않아도 된다.

(C#도 저거랑 똑같은 이름으로 있는듯?)

http://download.oracle.com/javase/1.4.2/docs/api/java/lang/RuntimeException.html

public class RuntimeException

extends Exception

RuntimeException is the superclass of those exceptions that can be thrown during the normal operation of the Java Virtual Machine.

A method is not required to declare in its throws clause any subclasses of RuntimeException that might be thrown during the execution of the method but not caught.