Hi, thanks for your answer.

The format is "RDF/XML-ABBREV". When the code below is executed, a window appears with 4 text fields and buttons Next, back, add, modify and remove. The button Next means move to the next instance of the Person class and displays the values of DatatypeProperties for this instance in text fields.
One click on Next button -> display on text fields values for the DatatypeProperties of Instance 1; Two clicks on Next button -> display on text fields values for the DatatypeProperties of Instance 2; etc.
But this button doesn't work. The text fields are empty.

Code:
    //ontology
    public class Onto 
    {
        (...)   
        public Onto (){
        model = ModelFactory.createOntologyModel(OntModelSpec.OWL_DL_MEM);
        (...)        
        //Classes
        (...)       
        
        //Sub-classes
        (...)
        
        }
    //ActionAdd for Add button- It works!
    public class ActionAjoutPersonne extends Onto implements ActionListener
    {
        
        public void actionPerformed(ActionEvent evt)
        {
                  
            Onto f;
                        
            f = new Onto();
    
            
            for(int i=0;i<4;i++)
            {
                
                            
                tabTF[i].getText();    
                Resource p1 = model.createResource(uriBase+tabTF[0].getText());
                p1.addProperty(RDF.type, f.personne);
                
                if (i==0) 
                {
                    p1.addProperty(f.aPourPrenom, tabTF[i].getText());
                    
                }
                if (i==1)
                {
                    p1.addProperty(f.aPourNom, tabTF[i].getText());
                }
                if (i==2)
                {
                    
                    p1.addProperty(f.aDateNaiss, tabTF[i].getText());
                }
                if (i==3)
                {
                    if (tabTF[i].getText().equals("F"))
                    {
                        p1.addProperty(f.aGenre, tabTF[i].getText());
                        p1.addProperty(RDF.type, f.femme);
                    }
                    else 
                        if (tabTF[i].getText().equals("H"))
                        {
                            p1.addProperty(f.aGenre, tabTF[i].getText());
                            p1.addProperty(RDF.type, f.homme);
                        }
                }
                
                StringWriter sw = new StringWriter();
                model.write(sw, "RDF/XML-ABBREV");
                String owlCode = sw.toString();
                File file = new File("d:/teste20.rdf");
                try{
                    FileWriter fw = new FileWriter(file);
                    fw.write(owlCode);
                    fw.close();
                } catch(FileNotFoundException fnfe){
                    fnfe.printStackTrace();} 
                catch(IOException ioe){
                        ioe.printStackTrace();
                }    
                
            }
            
        }
        }
    
    //ActionNext - for next button: it does not work
    class ActionSuivant extends Onto implements ActionListener
    {
        public void actionPerformed(ActionEvent evt)
        {
                    
            Onto s = new Onto();
            int indice=1;
            String []M= new String [10];
            
            //Read RDF File
            InputStream in = FileManager.get().open("d:\teste20.rdf");
            if (in == null) 
            {
              throw new IllegalArgumentException("File: " + "d:\teste20.rdf" + " not found");
            }
            s.model.read(in, null);
                
            //Search instances of Personne Class            
            ExtendedIterator instances=s.personne.listInstances();
                    
            indice++;
            for(int p=0;p<10;p++) //10 instances
            {
                while (instances.hasNext())
                {
                     Individual thisInstance = (Individual) instances.next();
                     M[p]= thisInstance.getLocalName();
                     
                    if(p==indice)
                    { 
                      tabTF[0].setText((thisInstance.getPropertyResourceValue(s.aPourPrenom)).toString());
                      tabTF[1].setText((thisInstance.getPropertyResourceValue(s.aPourNom)).toString());
                      tabTF[2].setText((thisInstance.getPropertyResourceValue(s.aDateNaiss)).toString());
                    }
                 }
             }
        }
    }
    
   
    }