CODEWITHSUNDEEP
javaexceptiontry-catch-finally
Cyril
Cyril

Reputation: 495

ClassNotFoundException I didn't succeed to catch

I read a lot of pages about the try/catch/finally process in java, but I didn't succeed to catch the ClassNotFoundException in my code. I used a for loop to open and save in rdfxml format every file in a directory I give as the argument. What I want is when I'm performing the code I get the e.getmessage() and the loop continue to treat the next file.

The problem is my script works perfectly fine but I don't receive the e.getmessage() when the ClassNotFoundException occurs.

@SuppressWarnings("finally")
public static void main(String[] args) {

    File dir = new File(args[0]);
    File[] directoryListing = dir.listFiles();

    if (directoryListing != null) {
        for (File owlFile : directoryListing){
            String name = owlFile.getName();
                    try {
                        translateOwlToRdfXml(owlFile,name);
                    }
                    catch (OWLOntologyCreationException|OWLOntologyStorageException|ClassNotFoundException e) {
                        System.out.println(name + " has not been saved into RDF/XML;");
                        System.out.println(e.getMessage());
                        }
                    finally {
                        continue;
                    }
                }

            }
        }


    static void translateOwlToRdfXml(File owlFile, String name) throws OWLOntologyCreationException, OWLOntologyStorageException, ClassNotFoundException {

            OWLOntologyManager manager = OWLManager.createOWLOntologyManager();

        System.out.println("Loaded ontology: " + name);
        OWLOntology ontology;
        ontology = manager.loadOntologyFromOntologyDocument(owlFile);
        RDFXMLOntologyFormat rdfxmlFormat = new RDFXMLOntologyFormat();

            manager.saveOntology(ontology, rdfxmlFormat, IRI.create(owlFile));
        System.out.println("Saved ontology in RDF/OWL: " + name);

    }
}

When I don't write the "finally" block, I receive this message:

Exception in thread "main" java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58)
Caused by: java.lang.NoClassDefFoundError: com/github/jsonldjava/core/JsonLdError
    at org.openrdf.rio.jsonld.JSONLDParserFactory.getParser(JSONLDParserFactory.java:37)
    at org.openrdf.rio.Rio.createParser(Rio.java:195)
    at org.semanticweb.owlapi.rio.RioParserImpl.parseDocumentSource(RioParserImpl.java:241)
    at org.semanticweb.owlapi.rio.RioParserImpl.parse(RioParserImpl.java:191)
    at uk.ac.manchester.cs.owl.owlapi.ParsableOWLOntologyFactory.loadOWLOntology(ParsableOWLOntologyFactory.java:161)
    at uk.ac.manchester.cs.owl.owlapi.OWLOntologyManagerImpl.loadOntology(OWLOntologyManagerImpl.java:975)
    at uk.ac.manchester.cs.owl.owlapi.OWLOntologyManagerImpl.loadOntologyFromOntologyDocument(OWLOntologyManagerImpl.java:913)
    at uk.ac.manchester.cs.owl.owlapi.OWLOntologyManagerImpl.loadOntologyFromOntologyDocument(OWLOntologyManagerImpl.java:928)
    at owl2rdf.owl2rdf.translateOwlToRdfXml(owl2rdf.java:57)
    at owl2rdf.owl2rdf.main(owl2rdf.java:32)
    ... 5 more
Caused by: java.lang.ClassNotFoundException: com.github.jsonldjava.core.JsonLdError
    at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 15 more

But when I write the "finally", I receive nothing and the code continue to treat the next file. I thought I don't understand clearly how try/catch and throw methods work.

Thanks in advance

Upvotes: 5

Views: 6272

Answers (3)

Dakshinamurthy Karra
Dakshinamurthy Karra

Reputation: 5463

translateOwlToRdfXml throwing InvocationTargetException. 

InvocationTargetException is a checked exception that wraps
an exception thrown by an invoked method or constructor.

You need to catch this exception and then use getTargetException to get the NoClassDefFoundError. From there you can get the getCause gives you the wrapper ClassNotFoundException.

Upvotes: 0

Erwan C.
Erwan C.

Reputation: 719

You only catch exceptions you list in catch(...). The stack trace shows the exception in the main method is an NoClassDefFoundError.

To solve it replace 

catch (OWLOntologyCreationException|OWLOntologyStorageException|ClassNotFoundException e) {
      System.out.println(name + " has not been saved into RDF/XML;");
      System.out.println(e.getMessage());
}

By (here you catch all exceptions)

catch (Exception e) {
         System.out.println(name + " has not been saved into RDF/XML;");
         System.out.println(e.getMessage());
}

Or by

catch (OWLOntologyCreationException|OWLOntologyStorageException
|ClassNotFoundException|NoClassDefFoundErrore) {
             System.out.println(name + " has not been saved into RDF/XML;");
             System.out.println(e.getMessage());
}

Upvotes: 3

pkalinow
pkalinow

Reputation: 1741

Try catching NoClassDefFoundError instead of ClassNotFoundException. The latter is wrapped by the former.

See the following stack trace fragment - it means that the method throws NoClassDefFoundError:

Caused by: java.lang.NoClassDefFoundError: com/github/jsonldjava/core/JsonLdError
at org.openrdf.rio.jsonld.JSONLDParserFactory.getParser(JSONLDParserFactory.java:37)
at org.openrdf.rio.Rio.createParser(Rio.java:195)
at org.semanticweb.owlapi.rio.RioParserImpl.parseDocumentSource(RioParserImpl.java:241)
at org.semanticweb.owlapi.rio.RioParserImpl.parse(RioParserImpl.java:191)
at uk.ac.manchester.cs.owl.owlapi.ParsableOWLOntologyFactory.loadOWLOntology(ParsableOWLOntologyFactory.java:161)
at uk.ac.manchester.cs.owl.owlapi.OWLOntologyManagerImpl.loadOntology(OWLOntologyManagerImpl.java:975)
at uk.ac.manchester.cs.owl.owlapi.OWLOntologyManagerImpl.loadOntologyFromOntologyDocument(OWLOntologyManagerImpl.java:913)
at uk.ac.manchester.cs.owl.owlapi.OWLOntologyManagerImpl.loadOntologyFromOntologyDocument(OWLOntologyManagerImpl.java:928)
at owl2rdf.owl2rdf.translateOwlToRdfXml(owl2rdf.java:57)

Upvotes: 1

Related Questions