Exceptoin中有一个特殊的子类异常RuntimeException 运行时异常。



如果在函数内容抛出该异常，函数上可以不用声明，编译一样通过。



如果在函数上声明了该异常。调用者可以不用进行处理。编译一样通过；



之所以不用在函数声明，是因为不需要让调用者处理。

当该异常发生，希望程序停止。因为在运行时，出现了无法继续运算的情况，希望停止程序后，

对代码进行修正。









自定义异常时：如果该异常的发生，无法在继续进行运算，

就让自定义异常继承RuntimeException。





对于异常分两种：

1，编译时被检测的异常。

　　

2，编译时不被检测的异常(运行时异常。RuntimeException以及其子类)

-Exceptoin has a special subclass of RuntimeException exception runtime exceptions. If the contents of this exception is thrown in the function, the function can not declare, as compiled through. If the function is declared on the exception. The caller can not be processed. As compiled through　why do not the function declaration, because the caller does not need to deal with. When this exception occurs, you want the program to stop. Because at run time, there has been unable to continue operations, in the hope to stop the program after the code be amended. Custom Exception: If the exception occurs, you can not continue operations, let custom exception inheritance RuntimeException. For the exception of two kinds: one, to be detected at compile time exception. 2, the compiler is not detected abnormality (runtime exception. RuntimeException and its subclasses)