[protege-discussion] nullpointer exception in the loadKnowledgeBase method

[Tania Tudorache]

Olivier,

I have documented on the wiki how to load an ontology stored in a 
Protege frames database:

http://protege.cim3.net/cgi-bin/wiki.pl?HowToUseDatabaseBackend

Tania

Olivier Mocquais RD-BIZZ wrote:
> Hi,
>
> I want to save a jdbc knowledge base into a pprj file.
>
> I use the Protégé API and this java code, but it doesn't work, I have a 
> NullPointerException when the loadKnowledgeBase method is called. The 
> database and the table exists with many information.
>
> WARNING: Unable to load knowledgebase jdbc:mysql://localhost/protege -- 
> java.lang.NullPointerException
>     at 
> edu.stanford.smi.protege.storage.database.DatabaseKnowledgeBaseFactory.initializeKB(Unknown 
> Source)
>     at 
> edu.stanford.smi.protege.storage.database.DatabaseKnowledgeBaseFactory.loadKnowledgeBase(Unknown 
> Source)
>
> String username = "root";
> String password = "system";
> String driver = "com.mysql.jdbc.Driver";
> String tablename = "protegekb";
> Collection errors = new ArrayList();
> DatabaseKnowledgeBaseFactory myFactory = new DatabaseKnowledgeBaseFactory();
> Project prj = Project.createNewProject(myFactory, errors);
> prj.setProjectFilePath("myproject.pprj");
> prj.setKnowledgeBaseFactory(myFactory);
> KnowledgeBase kb = prj.getKnowledgeBase();
> myFactory.loadKnowledgeBase(kb, driver, 
> "jdbc:mysql://localhost/protege", username, password, tablename, errors);
> errors = new ArrayList();
> prj.save(errors);
>
> Thanks for any help in order to resolve my problem.
>
> Regards
>
> Olivier
>
>
> The full Trace:
> CONFIG: Protege 3.2.1 Build 365, JVM 1.5.0_10-b03, memory=66M, Windows 
> XP, encoding=UTF-8, language=fr, country=FR
> WARNING: Look and feel not found: 
> com.jgoodies.looks.plastic.PlasticLookAndFeel -- 
> SystemUtilities.setLookAndFeel()
> CONFIG: Loaded plugin edu.stanford.smi.protegex.owl - OWL Plugin
> CONFIG: Loaded plugin ca.uvic.cs.chisel.jambalaya - Jambalaya
> CONFIG: Loaded plugin dfki.protege.ontoviz
> CONFIG: Loaded plugin edu.stanford.smi.protege.script - Script Plugin
> CONFIG: Loaded plugin edu.stanford.smi.protegex.standard_extensions - 
> Graph Widget, Table Widget
> CONFIG: Loaded plugin edu.stanford.smi.protege.stringsearch - String 
> Search Tab
> CONFIG: Loaded plugin edu.stanford.smi.protegex.rdf_backend - RDF Backend
> WARNING: Duplicate plugin: 
> edu.stanford.smi.protegex.storage.rdf.configurable.RDFExportPlugin -- 
> PluginUtilities.checkPlugin()
> WARNING: Duplicate plugin: 
> edu.stanford.smi.protegex.widget.oil.ExpressionFieldWidget -- 
> PluginUtilities.checkPlugin()
> WARNING: Duplicate plugin: 
> edu.stanford.smi.protegex.storage.rdf.configurable.RDFCreateProjectPlugin 
> -- PluginUtilities.checkPlugin()
> WARNING: Duplicate plugin: 
> edu.stanford.smi.protegex.storage.rdf.configurable.RDFExportProjectPlugin 
> -- PluginUtilities.checkPlugin()
> WARNING: Duplicate plugin: 
> edu.stanford.smi.protegex.widget.oil.ExpressionListWidget -- 
> PluginUtilities.checkPlugin()
> WARNING: Duplicate plugin: 
> edu.stanford.smi.protegex.storage.rdf.configurable.RDFCBackend -- 
> PluginUtilities.checkPlugin()
> CONFIG: Loaded plugin edu.stanford.smi.protegex.changes - Changes tab
> CONFIG: Loaded plugin edu.stanford.smi.protegex.pal_tabs - PAL Tabs
> CONFIG: Loaded plugin edu.stanford.smi.protegex.ezpal - EZPal Tab
> CONFIG: Loaded plugin edu.stanford.smi.protegex.facets_tab
> CONFIG: Loaded plugin edu.stanford.smi.protegex.instance_tree
> CONFIG: Loaded plugin edu.stanford.smi.protegex.prompt - PROMPT Tab
> CONFIG: Loaded plugin edu.stanford.smi.protegex.psm - PSM Librarian
> CONFIG: Loaded plugin edu.stanford.smi.protegex.umls_tab - UMLS Tab
> CONFIG: Loaded plugin edu.stanford.smi.protegex.wordnet - WordNet Tab
> CONFIG: Loaded plugin edu.stanford.smi.protegex.xml_tab - XML Tab
> CONFIG: Loaded plugin edu.washington.datagenie
> CONFIG: Loaded plugin org.algernon - Algernon
> CONFIG: Loaded plugin se.liu.ida.JessTab - JessTab Plugin
> CONFIG: Loaded plugin uk.ac.iam.soton.akt.tgviztab - TGVizTab
> CONFIG: Loaded plugin uk.ac.man.cs.mig.coode.debugger
> CONFIG: Loaded plugin uk.ac.man.cs.mig.coode.manchesterowlsyntaxeditor
> CONFIG: Loaded plugin uk.ac.man.cs.mig.coode.owldoc
> CONFIG: Loaded plugin uk.ac.man.cs.mig.coode.owlindividualstab
> CONFIG: Loaded plugin uk.ac.man.cs.mig.coode.owlunittest
> CONFIG: Loaded plugin uk.ac.man.cs.mig.coode.owlviz
> CONFIG: Loaded plugin uk.ac.man.cs.mig.coode.protege.wizard - Basic Wizards
> CONFIG: Loaded plugin uk.ac.man.cs.mig.coode.protege.wizard.owl - OWL 
> Wizards
> WARNING: Unable to load knowledgebase jdbc:mysql://localhost/protege -- 
> java.lang.NullPointerException
>     at 
> edu.stanford.smi.protege.storage.database.DatabaseKnowledgeBaseFactory.initializeKB(Unknown 
> Source)
>     at 
> edu.stanford.smi.protege.storage.database.DatabaseKnowledgeBaseFactory.loadKnowledgeBase(Unknown 
> Source)
>
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