When you need to execute the same SQL statement (in general an UPDATE) multiple times with different parameter values you can use the PrepareStatement method like this:

Connection conn=null;PreparedStatement pst=null;String[] nm=new String[3];int[] nc=new int[3];...try {nm[0]="Costescu",nm[1]="Alexandrescu",nm[2]="Popovici";nc[0]=234423;nc[1]=123344;nc[2]=534562;pst=conn.prepareStatement("UPDATE Table1 SET Nume=? WHERE Nr_cont=?");     for(int i=0;i<=2;i++)         {         pst.setString(1,nm[i]);         pst.setInt(2,nc[i]);         pst.executeUpdate();         }     }catch (SQLException e){System.out.println(e.getMessage());}...