什么时候编译器要求我捕获异常？

Question

class MyException extends Exception {
    MyException() {}
    MyException(String msg) { super(msg);}
}
public class NewException {

    static void f() throws MyException {
        System.out.println("throwing exception from f()");
        throw new ClassCastException();
    }
    static void g() throws MyException {
        System.out.println("throwing exception from g()");
        throw new MyException("parametrized ");
    }
    public static void main(String ...strings ) {
        try { 
            f();
        }
        catch(MyException e) {
            e.printStackTrace(System.out);
        }
        try {
            g();
        }
        catch(MyException e) {
            e.printStackTrace(System.out);
        }
    }
}

在函数f()中,我指定将抛出"MyException"异常,实际上我抛出了一些与MyException无关的其他异常,但编译器仍然没有抱怨.为什么？

Answer 1

ClassCastExceptionextends RuntimeException,表示它未被选中,因此编译器不需要您处理它.

来自Javadoc RuntimeException:

一个方法不需要在其throws子句中声明RuntimeException的任何子类,这些子类可能在方法执行期间抛出但未捕获.