运行时异常

运行时异常与其他异常的不同之处在于，抛出运行时异常的方法不需要用throws声明，
以下代码将打印
Inside throwOne.
finally executing.
(然后抛出运行时异常):
Exception in thread "main" java.lang.RuntimeException...

public class ThrowDemo{
  static void throwOne(){
    System.out.println("Inside throwOne.");
    throw new RuntimeException();
    //throw new IllegalAccessException("demo");
  }
  public static void main(String[] args){
    try{
      //System.out.println("Hello world!");
      throwOne();
    }finally {
      System.out.println("finally executing.");
    }

  }
}

运行时异常又称为未检查异常，另有一类异常为检查异常，常见的检查异常有：
ClassNotFoundException
CloneNotSupportedException
IllegalAccessException
InstantiationException
InterruptedException
NosuchFieldException
NoSuchMethodException
等等。