مشكلة Unknown column in where clause

السلام عليكم و رحمة الله و بركاته.

عندي مشكلة في الكود التالي.

public void Mots() {
    int i = 0;
    try {
        Connection con = DriverManager.getConnection("jdbc:mysql://localhost/lamsaf", "dbzakaria", "dbzakaria");
        Statement stmt = con.createStatement();
        ResultSet nive = stmt.executeQuery(" select " + test() + " from Utilisateur WHERE username = " + user);
        ResultSet rs = stmt.executeQuery("select mot from " + categorie + " WHERE niveau = " + nive.getInt(1) + "");
        while (rs.next()) {
            m[i] = rs.getString(1);
            System.out.println(m[i]);
            i++;
        }
        while (nive.next()) {
            niveau = nive.getInt(1);
        }
        con.close();
    } catch (Exception e) {
        System.out.println(e.getMessage());
    }
}

نتيجة التشغيل:

Unknown column 'moha' in 'where clause'

هل يمكنكم مساعدتي و شكراً.