Thinking in Java ：关于Java在异常处理中的缺陷

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/coderALEX/article/details/85298683

//How an exception can be lost.
class VeryImportantException extends Exception {
    private static final long serialVersionUID = 1L;

    public String toString() {
        return "A very important exception!";
    }
}

class HoHumException extends Exception {
    private static final long serialVersionUID = 1L;

    public String toString() {
        return "A trivial exception";
    }
}

public class LostMessage {
    void f() throws VeryImportantException {
        throw new VeryImportantException();
    }

    void dispose() throws HoHumException {
        throw new HoHumException();
    }

    public static void main(String[] args) {
        try {
            LostMessage lm = new LostMessage();
            try {
                lm.f();
            } finally {
                lm.dispose();
            }
        } catch (Exception e) {
            System.out.println(e);
        }
    }
} /* Output:
  A trivial exception
  *///:~

上述代码运行后可以发现VeryImportantException被第二个异常覆盖掉了，这是一个致命的缺陷：关键信息丢失了

除了上面这种还有另一个更简单的隐藏异常的方法：finally中return

public class ExceptionSilencer {
    public static void main(String[] args) {
        try {
            throw new RuntimeException();
        } finally {
            // Using ‘return’ inside the finally block
            // will silence any thrown exception.
            return;
        }
    }
} ///:~