[jira] [Commented] (JENA-505) NPE in the OWL class

["Andy Seaborne (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JENA-505?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13734698#comment-13734698 ] 

Andy Seaborne commented on JENA-505:
------------------------------------

When I run:

{noformat}
public static void main( String[] args ) {
   Model model = FileManager.get().loadModel("http://example.org","http://example.org","RDF/XML");
   System.out.println("DONE") ;
    }
{noformat}

I get a RIOT exception (correct - http://example.org isn't RDF/XML), not NPE from class OWL.

To get that sort of error in OWL, then it needs to happen as part of complex class initialization.

Do you have a complete, standalone example?

What is your classpath?  What is the stacktrace?
                
> NPE in the OWL class
> --------------------
>
>                 Key: JENA-505
>                 URL: https://issues.apache.org/jira/browse/JENA-505
>             Project: Apache Jena
>          Issue Type: Bug
>          Components: Jena
>    Affects Versions: Jena 2.10.1
>            Reporter: Piotr Hołubowicz
>
> The error happens when you try to load a file using the file manager in Jena 2.10.1, for example
> {code}
> model = FileManager.get().loadModel("http://example.org","http://example.org","RDF/XML");
> {code}
> The reason is incorrect initialization of variables in the OWL class. In the following code:
> {code}
>     public class OWL {
>         private static Model m_model = ModelFactory.createDefaultModel();
>         
>         public static final String NS = "http://www.w3.org/2002/07/owl#";
>         
>         public static String getURI() {return NS;}
>     
>     ...    
>         public static final Property sameAs = m_model.createProperty( "http://www.w3.org/2002/07/owl#sameAs" );
>     ...
> {code}
> a call to OWL.sameAs will result in a NPE because m_model is null. I guess that if you start with OWL.getURI(), then m_model will be evaluated first and there will be no error, which is why this never occurred before.
> I think that a solution would be to make m_model final as well.

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