靜態變量不能被解決或無法在現場

package project.groupsoftware.com; 

public class TrackBuilder { 


    public TrackBuilder(String name) { 
     m_track = new Track(name); 
    } 

    public static void addInitialTile(float length, int m_pointX, int m_pointY, double m_direction) { 
     InitialTile tile = new InitialTile(length, m_pointX, m_pointY, m_direction); 
     m_track.getTrackList().add(tile); 

    } 

    public void printTrackName() { 
     System.out.println("The name of Track"+ m_track.getTrackName()); 
    } 
    public static void addStraightTile(double length, Track track) { 
     StraightTile tile = new StraightTile(length); 
     m_track.getTrackList().add(tile); 
    } 

    public static void addCurvedTile(double angle, double radius, Track track) { 
     CurvedTile tile = new CurvedTile(angle, radius); 
     m_track.getTrackList().add(tile); 
    } 

    public static void removeLastTile() { 
     m_track.getTrackList().remove(m_track.getTrackList().size()-1); 
    } 

    public void loadTrack() { 
     // TODO implement here 
    } 

    public void saveTrack() { 
     // TODO implement here 
    } 

    public void updateDisplay() { 
     // TODO implement here 
    } 

    private static Track m_track; 

}

，我得到的錯誤是靜態變量不能被解決或無法在現場