java - Java RuntimeException和ArithmeticException

我有以下课程：

public class TryCatchExample {
    public static void main(String[] args) {
        try {
            System.out.println(1/0);
        }catch (RuntimeException e) {
            System.out.println("Runtime exception");
        } catch (ArithmeticException e) {
            System.out.println("Trying to divide by 0 is not ok.");
        }
        finally {
            System.out.println("The program will now exit");
        }
    }
}

编译器将引发以下错误：

TryCatchExample.java:10: error: exception ArithmeticException has already been caught
        } catch (ArithmeticException e) {
          ^
1 error

为什么会发生这种情况？ ArithmeticException是RuntimeException的子集，所以这会抛出RuntimeException还是ArithmeticException？

谢谢！

最佳答案

ArithmeticException是RuntimeException的子类，这意味着它已经由catch (RuntimeException e) ...分支处理。

您可以重新排序分支，以便首先捕获ArithmeticException，其他任何RuntimeException都将落入下一个分支：

try {
    System.out.println(1 / 0);
} catch (ArithmeticException e) {
    System.out.println("Trying to divide by 0 is not ok.");
} catch (RuntimeException e) {
    System.out.println("Runtime exception");
} finally {
    System.out.println("The program will now exit");
}