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.

public class ChuckNorrisException extends Exception {
    public ChuckNorrisException() {
        System.exit(1);
    }
}

(当然，从技术上讲，这个异常永远不会被真正抛出，但是一个正确的ChuckNorrisException不能被抛出——它会先抛出你。)

在构造函数中，可以启动一个反复调用originalThread的线程。停止(ChuckNorisException.this)

线程可以重复捕获异常，但会一直抛出异常，直到异常死亡。

在当前线程上模拟一个未捕获的异常是很容易的。这将触发未捕获异常的常规行为，从而在语义上完成工作。然而，它并不一定会停止当前线程的执行，因为实际上并没有抛出异常。

Throwable exception = /* ... */;
Thread currentThread = Thread.currentThread();
Thread.UncaughtExceptionHandler uncaughtExceptionHandler =
    currentThread.getUncaughtExceptionHandler();
uncaughtExceptionHandler.uncaughtException(currentThread, exception);
// May be reachable, depending on the uncaught exception handler.

这实际上在(非常罕见的)情况下很有用，例如当需要适当的错误处理时，但该方法从捕获(并丢弃)任何Throwable的框架中调用。

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。