try 
{
    System.out.println("hip1" );
        fname = rep + System.getProperty("file.separator" ) + id + "_truc.pdf";
    System.out.println("hip2" );
        sortie=  new FileOutputStream(fname);                
    System.out.println("hip3" );
        ByteArrayOutputStream out = new ByteArrayOutputStream();
    System.out.println("hip4" );
        Driver driver = new Driver(foFile, out); // ligne qui plante
    System.out.println("hip5" );
        driver.run();
    System.out.println("hip6" );
        byte[] content = out.toByteArray();    
    System.out.println("hip7" );            
        sortie.write (content);        
    System.out.println("hip8" );        
                    
}
catch (Exception ex)  // en desespoir de cause
{
    System.err.println("erreur de génération du PDF===>" );
    ex.printStackTrace();                                    
}    
finally 
{
    System.out.println("FIN RENDER FO" );
    /* snip */
        return fname;
}

1. try {
2.   throw new Exception();
3. } catch (Exception e) {
4.   return "catch";
5. } finally {
6.   return "finally";
7. }