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Re: e==null? really?

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From	Eric Sosman <esosman@ieee-dot-org.invalid>
Newsgroups	comp.lang.java.programmer
Subject	Re: e==null? really?
Date	Fri, 13 Jul 2012 10:48:13 -0400
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On 7/13/2012 10:29 AM, markspace wrote:
> On 7/13/2012 7:18 AM, bob smith wrote:
>> Is it possible to do this in Java?
>>
>> throw null;
>
>
> Yes. JLS:
>
> <http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.18>
>
>
> "throw Expression ;
>
> The Expression in a throw statement must denote either 1) a variable or
> value of a reference type which is assignable (§5.2) to the type
> Throwable, or 2) the null reference..."

     Interesting. Reading onward, though, we find

	"If evaluation of the Expression completes normally,
	producing a null value, then an instance V' of class
	NullPointerException is created and thrown instead of
	null. [...]"

... which leaves a bit of a mystery.  The O.P.'s example was
(fleshed out somewhat)

	try {
	    throw null;
	} catch (Exception e) {
	    // e is null here!
	}

... but according to the JLS that shouldn't have happened.  Bug?

-- 
Eric Sosman
esosman@ieee-dot-org.invalid

Thread

e==null?  really? bob smith <bob@coolfone.comze.com> - 2012-07-13 07:18 -0700
  Re: e==null?  really? markspace <-@.> - 2012-07-13 07:29 -0700
    Re: e==null?  really? Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-07-13 10:48 -0400
      Re: e==null?  really? markspace <-@.> - 2012-07-13 08:22 -0700
        Re: e==null?  really? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-07-13 09:35 -0700
      Re: e==null?  really? Lew <lewbloch@gmail.com> - 2012-07-13 13:11 -0700
        Re: e==null?  really? Joerg Meier <joergmmeier@arcor.de> - 2012-07-13 22:55 +0200
          Re: e==null?  really? "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-07-13 17:01 -0400
    Re: e==null?  really? Lew <lewbloch@gmail.com> - 2012-07-13 13:09 -0700
  Re: e==null?  really? Roedy Green <see_website@mindprod.com.invalid> - 2012-07-13 12:09 -0700
    Re: e==null?  really? Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2012-07-13 23:06 +0200
      Re: e==null?  really? Roedy Green <see_website@mindprod.com.invalid> - 2012-07-14 06:30 -0700

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