[JAVA] Errore: cannot reference... before supertype constructor has been called

[gbu123]

ciao
la compilazione della sottoclasse mi da errore :
cannot reference ArtBaseInt_1 before supertype constructor has beencalled.

//superclasse 
public class ArtBase 
{
    // instance variables 
     public int  ArtBaseInt_1 ;
     public int  ArtBaseInt_2 ;
     public char ArtBaseChr_1 ;
     public char ArtBaseChr_2 ; 
     public String ArtBaseStr_1 ; 
     public String ArtBaseStr_2 ; 

    /**
     * Constructor for objects of class ArticoloBase
     */
   ArtBase (int intero_1,int intero_2,
            char carattere_1,char carattere_2,
            String stringa_1,String stringa_2)  
      { 
       ArtBaseInt_1  = intero_1 ; 
       ArtBaseInt_2  = intero_2 ; 
       ArtBaseChr_1  = carattere_1 ; 
       ArtBaseChr_2  = carattere_2 ; 
       ArtBaseStr_1  = stringa_1 ;         
       ArtBaseStr_2  = stringa_2 ;         
      }  

ecc. ecc.

//sottoclasse 
public class ArtMoto extends ArtBase
{
    // instance variables 
    private int  ArtMotoInt_3 ;
    private int  ArtMotoInt_4 ;
    private char ArtMotoChr_3 ;
    private char ArtMotoChr_4 ; 
    private String ArtMotoStr_3 ; 
    private String ArtMotoStr_4 ; 

    /**
     * Constructor for objects of class ArtMoto 
     */
   ArtMoto (int intero_1,int intero_2
           ,char carattere_1,char carattere_2
           ,String Stringa_1,String Stringa_2  
           ,int intero_3,int intero_4
           ,char carattere_3,char carattere_4
           ,String Stringa_3,String Stringa_4
           )       
      { 
       super( 
             ArtBaseInt_1  = intero_1 , 
             ArtMotoInt_2  = intero_2 , 
             ArtMotoChr_1  = carattere_1 , 
             ArtMotoChr_2  = carattere_2 , 
             ArtMotoStr__1  = Stringa_1 ,         
             ArtMotoStr__2  = Stringa_2 ) ;         
       ArtMotoInt_3  = intero_3 ; 
       ArtMotoInt_4  = intero_4 ; 
       ArtMotoChr_3  = carattere_3 ; 
       ArtMotoChr_4  = carattere_4 ; 
       ArtMotoStr_3  = Stringa_3 ;         
       ArtMotoStr_4  = Stringa_4 ;         
      }  

ecc. ecc.

dove sbaglio ?
grazie , ciao