是否有可能在Java中构造一段代码,使假设的Java .lang. chucknorrisexception无法捕获?

我想到的是使用拦截器或面向方面的编程。


当前回答

Two fundamental problems with exception handling in Java are that it uses the type of an exception to indicate whether action should be taken based upon it, and that anything which takes action based upon an exception (i.e. "catch"es it) is presumed to resolve the underlying condition. It would be useful to have a means by which an exception object could decide which handlers should execute, and whether the handlers that have executed so far have cleaned things up enough for the present method to satisfy its exit conditions. While this could be used to make "uncatchable" exceptions, two bigger uses would be to (1) make exceptions which will only be considered handled when they're caught by code that actually knows how to deal with them, and (2) allow for sensible handling of exceptions which occur in a finally block (if a FooException during a finally block during the unwinding of a BarException, both exceptions should propagate up the call stack; both should be catchable, but unwinding should continue until both have been caught). Unfortunately, I don't think there would be any way to make existing exception-handling code work that way without breaking things.

其他回答

经过思考,我成功地创建了一个不可捕捉的异常。然而,我选择取名为JulesWinnfield,而不是Chuck,因为这是一个蘑菇云的母亲例外。此外,它可能不是你想要的,但它肯定不会被捕捉到。观察:

public static class JulesWinnfield extends Exception
{
    JulesWinnfield()
    {
        System.err.println("Say 'What' again! I dare you! I double dare you!");
        System.exit(25-17); // And you shall know I am the LORD
    }
}
    
    
public static void main(String[] args)
{       
    try
    {
        throw new JulesWinnfield();
    } 
    catch(JulesWinnfield jw)
    {
        System.out.println("There's a word for that Jules - a bum");
    }
}

果不其然!未捕获异常。

输出:

运行: 再说一遍“什么”!我敢打赌!我真不敢相信你! Java结果:8 BUILD SUCCESSFUL(总时间:0秒)

等我有更多的时间,我再看看能不能想出别的办法。

还有,看看这个:

public static class JulesWinnfield extends Exception
{
    JulesWinnfield() throws JulesWinnfield, VincentVega
    {
        throw new VincentVega();
    }
}

public static class VincentVega extends Exception
{
    VincentVega() throws JulesWinnfield, VincentVega
    {
        throw new JulesWinnfield();
    }
}


public static void main(String[] args) throws VincentVega
{
    
    try
    {
        throw new JulesWinnfield();
    }
    catch(JulesWinnfield jw)
    {
        
    }
    catch(VincentVega vv)
    {
        
    }
}

导致堆栈溢出-同样,异常仍然未捕获。

任何代码都可以捕获Throwable。所以不,无论你创建什么异常都会是Throwable的子类并且会被捕获。

不。Java中的所有异常都必须成为Java .lang的子类。虽然这可能不是一个好的实践,但你可以像这样捕获每种类型的异常:

try {
    //Stuff
} catch ( Throwable T ){
    //Doesn't matter what it was, I caught it.
}

有关更多信息,请参阅java.lang.Throwable文档。

如果您试图避免检查异常(必须显式处理的异常),那么您将希望继承Error或RuntimeException类。

抛出的任何异常都必须扩展Throwable,因此总是可以捕获它。所以答案是否定的。

如果你想让它难以处理,你可以重写方法getCause(), getMessage(), getStackTrace(), toString()抛出另一个java.lang.ChuckNorrisException。

实际上,公认的答案并不是那么好,因为Java需要在没有验证的情况下运行,即代码在正常情况下无法工作。

AspectJ拯救了真正的解决方案!

异常类:

package de.scrum_master.app;

public class ChuckNorrisException extends RuntimeException {
    public ChuckNorrisException(String message) {
        super(message);
    }
}

方面:

package de.scrum_master.aspect;

import de.scrum_master.app.ChuckNorrisException;

public aspect ChuckNorrisAspect {
    before(ChuckNorrisException chuck) : handler(*) && args(chuck) {
        System.out.println("Somebody is trying to catch Chuck Norris - LOL!");
        throw chuck;
    }
}

示例应用程序:

package de.scrum_master.app;

public class Application {
    public static void main(String[] args) {
        catchAllMethod();
    }

    private static void catchAllMethod() {
        try {
            exceptionThrowingMethod();
        }
        catch (Throwable t) {
            System.out.println("Gotcha, " + t.getClass().getSimpleName() + "!");
        }
    }

    private static void exceptionThrowingMethod() {
        throw new ChuckNorrisException("Catch me if you can!");
    }
}

输出:

Somebody is trying to catch Chuck Norris - LOL!
Exception in thread "main" de.scrum_master.app.ChuckNorrisException: Catch me if you can!
    at de.scrum_master.app.Application.exceptionThrowingMethod(Application.java:18)
    at de.scrum_master.app.Application.catchAllMethod(Application.java:10)
    at de.scrum_master.app.Application.main(Application.java:5)