If an answer on this already exist, my apologies i've not found on this question...

is this statement correct if i want presice actions on integers from -2 to 0, and for those between 1 and 6 apply the same methods with only my integer who'll change ?

Like this:

    public void setCaseGUI(Point pt, int i, boolean b){
        plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setSelected(b);
        plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setIcon(null);

        switch(i) {
            case -2:    plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setText("F");
                        plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setForeground(Color.red);
                        break;

            case -1:    plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setText("B");
                        plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setForeground(Color.red);
                        break;

            case 0: plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setText("");
                    plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setForeground(null);
                    break;

            case 1: case 2: case 3: case 4: case 5: case 6: case 7:
            case 8: plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setText(String.valueOf(i));
                    plateau.cellule[(int)pt.getAbs()][(int)pt.getOrd()].setForeground(null);
                    break;

            default: System.out.println("Erreur de changement d'état/case !");
        }
    }

Please don't be too harsh on me i've started to learn dev only a few month ago