EDIT

package eu.etaxonomy.taxeditor.editor.workingSet;

import java.io.File;

import java.io.IOException;

import java.net.URISyntaxException;

import java.net.URL;

import javax.xml.bind.JAXBContext;

import javax.xml.bind.JAXBException;

import javax.xml.bind.Unmarshaller;

import org.bgbm.prometheus.xml.ONTOLOGYDETAILS;

import org.bgbm.prometheus.xml.TreeNode;

import org.eclipse.core.runtime.FileLocator;

import org.eclipse.core.runtime.Path;

import org.eclipse.core.runtime.Platform;

public class PrometheusOntology {

	public static ONTOLOGYDETAILS createOntology() {

		try {

		    URL url = null;

		    URL iconUrl = FileLocator.find(Platform.getBundle("eu.etaxonomy.taxeditor.editor"), new Path("icons/Ontology.xml"), null);

//		    URL url = PrometheusOntology.class.getResource("Ontology.xml");

			File file = null;

            try {

                file = new File(FileLocator.resolve(iconUrl).toURI());

            } catch (URISyntaxException | IOException e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            }

			JAXBContext jaxbContext = JAXBContext.newInstance(ONTOLOGYDETAILS.class, TreeNode.class);

			Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();

			ONTOLOGYDETAILS unmarshal = (ONTOLOGYDETAILS) jaxbUnmarshaller.unmarshal(file);

			return unmarshal;

		  } catch (JAXBException e) {

			e.printStackTrace();

		  }

		return null;

	}

	public static void main(String[] args) {

	    createOntology();

    }

}