Checked Exception 编译时异常 编译的时候检查你的代码可能在运行的时候抛出异常，这通常在编译的时候要去处理的。

RunnableException 运行时异常，可以编译通过，但如果不处理运行时会导致崩溃，需要对其进行try....catch...处理。

常见的RunnableException 有

//        int i = 3 / 0;                                  // ArithmeticException ，除数为0时的算法异常
//        List<String> list = new ArrayList<String>();
//        String s = list.get(0);                         //IndexOutOfBoundsException，
//        String [] str = new String[2];
//        String s = str[3];                              //ArrayIndexOutOfBoundsException
//        String str = "hello";
//        str.charAt(5);                                   //StringIndexOutOfBoundsException
//        Haha haha = null;
//        haha.sayHello("hello");                          //NullPointerException
//        Haha haha = new Haha();
//        haha.sayHello(new Object());                      //IllegalArgumentException(不合法参数)

//        int i = Integer.parseInt("aa");                   //NumberFormatException
//        Object o = new Integer(1);
//        System.out.println((String) o);                     //ClassCastException