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From OC <...@ocs.cz>
Subject Re: Non-Null Object Is Null
Date Wed, 13 Jul 2016 17:26:14 GMT
Scott,

> I guess the moral of the story is that if you use GGTS and suddenly something is acting
totally off the wall wacko, try cleaning everything, including deleting all the target folders.

with Java-based languages and toolchains, it is a good idea with about any IDE :)

E.g., my own toolchain brings havoc if one changes package (for the old .class in a wrong
place does not get deleted: I still haven't found a reasonably decent way to do that, short
of essentially switching off the whole incremental-build thing). And there's a plethora of
other and much less obvious problems in the, ahem, let's say exciting, world driven by classloaders.

All the best and congrats you have found the culprit,
OC

On 13. 7. 2016, at 18:33, Scott Arnold <sca7740@bjc.org> wrote:

> Good news.  I finally figured this out (mostly).  It was an issue with dirty compiled
code.  I am using Groovy Grails Tool Suite (GGTS).  It compiles the application artifacts
into two folders, a "target" folder and a "target-eclipse" folder.  I completely deleted both
of these folders, did a project clean, a Grails refresh dependencies, and on the next application
start the code was working as expected.  
> 
> This was incredibly bizarre and I apologize that it seems to have been more of an IDE
problem rather than a Groovy problem.  I guess the moral of the story is that if you use GGTS
and suddenly something is acting totally off the wall wacko, try cleaning everything, including
deleting all the target folders.
> 
> Thank you everyone who took a look at this.
> 
> -----Original Message-----
> From: Scott Arnold [mailto:sca7740@bjc.org] 
> Sent: Wednesday, July 13, 2016 11:20 AM
> To: users@groovy.apache.org
> Subject: RE: Non-Null Object Is Null
> 
> I decided to experiment a little with immediately after instantiation.  Here is what
that looked like:
> 
> ICF icf = new ICF();
> System.out.println("icf is " + icf);
> System.out.println("is it null?  " + (icf == null));
> 
> And the output...
> 
> icf is null
> is it null?  false
> 
> NullPointerException continues to happen if I try to call icf.getClass() at any point.
> 
> Could this have something to do with the code being inside a Groovy-ish loop?  The surrounding
code has this:
> 
> def result = client.search(tsr)  // web service call
> for (e in result.entries) {
> 	ICF icf = new ICF();
> 	System.out.println("icf is " + icf);
> 	System.out.println("is it null?  " + (icf == null));
> 	// ... more code
> }
> 
> An additional note -- the earlier capital "N" on null is not occurring -- I think it
was an accidental auto-correct in my original message.  It just prints "null" with lower-case
"n".
> 
> -----Original Message-----
> From: Scott Arnold [mailto:sca7740@bjc.org] 
> Sent: Wednesday, July 13, 2016 10:35 AM
> To: users@groovy.apache.org
> Subject: RE: Non-Null Object Is Null
> 
> Thought I would add a little more detail.  I'm using Groovy 2.3.7.  I thought this might
be somehow related to Groovy's NullObject, but you are supposed to be able to call getClass()
on NullObject based on info I have found online.  The very next line of my code is to just
call icf.getClass() and that is when the NullPointerException is thrown.
> 
> I'm going to go back and play around with the instantiation some more and see if that
adds any more clues.  I'm not sure what the repercussions are of using ICF icf (vs def icf)
are.
> 
> -----Original Message-----
> From: Scott Arnold [mailto:sca7740@bjc.org]
> Sent: Wednesday, July 13, 2016 10:01 AM
> To: users@groovy.apache.org
> Subject: Non-Null Object Is Null
> 
> I'm new to Groovy (lots of Java experience but almost no Groovy experience) and maybe
there is something very basic I am missing here, but I am running into the following issue
in a Grails app (but I think it's a not understanding Groovy issue).  I'm not sure I can break
it down any further than I already have, so I am kind of stumped about what I am doing wrong
here.
> 
> In case you know Grails and want some detail on where this code is happening, I'm working
on a pre-existing Grails app that calls a service from the BootStrap.groovy during application
startup.  The code I'm having a problem with is within the service class.
> 
> Here's the code snippet:
> 
> System.out.println("is icf null? " + (icf == null)); System.out.println("is icf not null?
" + (icf != null)); System.out.println("what is icf? " + icf);
> 
> And here's the output:
> 
> is icf null? false
> is icf not null? true
> what is icf? Null
> 
> If I try to call a method on icf, I get a NullPointerException.  However, earlier in
the code icf is created (currently it is created Java-style rather than using def, as in ICF
icf = new ICF()) and the code tries to set several property values within icf (e.g. icf.code
= suchandsuch) and none of that throws any errors.
> 
> What might be happening here?
> 
> Thanks.


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