public abstract class Constante {

    private static final int nbAscenceurMax = 10;
    private static final int nbEtage = 20;

    public static final int getNbEtage() {
        return nbEtage;
    }

    public static final int getNbAscenceur() {
        return nbAscenceurMax;
    }
}

package traitement;

public abstract class Constante {

    private static final int nbAscenceurMax = 10;
    private static final int nbEtage = 20;

    public static final int getNbEtage() {
        return nbEtage;
    }

    public static final int getNbAscenceur() {
        return nbAscenceurMax;
    }

	public static int getNumEtageMin() {
		// TODO Auto-generated method stub
		return 0;
	}
}

Update Constante.java