Hello Mike, Its the same code I have showed you (except that I changed variable names for simplicity), and there is no line of code that is missing. Where "a" is the EO property and when I check for it ( if(a != null) JRE throws NPE and when I check for if(a == null), JRE enjoys ), its throwing exception as stated. I believe this is a bug with JRE, and it seems to be fixed as per David's testing in later versions of JRE.
I think fix would be JRE shouldn't have unboxed it if its null... and they seems to have realized this mistake in later versions of JRE... But its wondering how a null & not null check differs in this world and they are not same from JRE perspective!!! If its an error it should have thrown error always... Thank You, Shravan Kumar. M ________________________________ From: Mike Schrag <[email protected]> To: Shravan Kumar. M <[email protected]> Cc: WO Dev Group <[email protected]> Sent: Sat, November 21, 2009 9:26:57 PM Subject: Re: [OT] Weird Boolean/ Wrapper class bug You're not pasting the real code, I don't think. I suspect you're just getting screwed by autoboxing in whatever code you're not showing. If you have: Boolean a = null; boolean b = a; That will result in a NPE as auto-unboxing attempts to unbox a into a boolean, which throws a NPE. Somewhere in the code you didn't include is an unbox into a boolean (little b) of your null Boolean. So, for instance: Boolean a = null; if (a) { } will NPE. Look more closely at the exact code, specifically the line of code that actually failing, and make sure you're not getting an unbox. ms On Nov 21, 2009, at 10:23 AM, Shravan Kumar. M wrote: Hello Group, > > >Boolean a = null; >if(a != null) >System.out.println("s"); >else >System.out.println("n"); >---------- >Above code block raises NullPointerException, where as below one runs >successfully!!! Same is the case with any wrapper class (Integer, Long, ...). >*Its wondering what it makes difference in checking (a != null) and (a == >null)? Its just an Object check rt!* > > >Exact exception: java.lang.NullPointerException at booleanValue() >---------- >Boolean a = null; >if(a == null) >System.out.println("s"); >else >System.out.println("n"); > > >Thank You, >Shravan Kumar. M >-------------------------------- >_______________________________________________ >Do not post admin requests to the list. They will be ignored. >Webobjects-dev mailing list ([email protected]) >Help/Unsubscribe/Update your Subscription: >http://lists.apple.com/mailman/options/webobjects-dev/mschrag%40mdimension.com > >This email sent to [email protected]
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