Anyone knows how to display a marker using J2MEMap?

[phpuser123]

I want to load a map and display a marker on it. However, the map is loaded but the marker is not visible ..Anyone knows what the problem is?

      UtilMidp.checkMIDP(this);  //Initialise the utility library...
        m_map=new MapDisplay();
        m_display=Display.getDisplay(this);
        GenericOverlay openStreeMap=new GenericOverlay("OpenStreeMap","http://tile.openstreetmap.org/!z!/!x!/!y!.png");
        //GenericOverlay openStreeMap=new GenericOverlay("GoogleMap","http://mt0.google.com/vt/x!&y=!&z=!.PNG");
        m_map.setMapProvider(0,openStreeMap);

        Track t=Track.getTrack(null, "Sample...");
        //henson.midp.Float x= 2;
        //Float x = new Float((long)(90));
        //Float z = new Float((long)(190));
        float y =37.803f;
        long lat = (long) Double.parseDouble("20");
        long lon = (long) Double.parseDouble("52");
        //m_map.gotoLonLat(x,  y);
       // m_map.gotoLonLat(x,y);
        Float x = new Float(lat);
        Float z = new Float(lon);
         Marker m=new Marker(x,z);
         //m.setLonLat(henson.midp.Float.SQRT3, henson.midp.Float.SQRT3)
       // m_map.
        m_map.gotoLonLat(90,190);
       
        
        System.out.println(m_map.getDist());
        System.out.println(m_map.getZoom());

       // Marker l=new Marker(x,y );

        
        t.addMarker(m);
        //m_map.displayTrack(t, false);

        m_display.setCurrent(m_map.getCanvas());
    }