Tabela duplicando valores[RESOLVIDO]

public void listarNum() throws Exception {
        
        armarioList = perArmario.listarNum();
        DefaultTableModel modelo = (DefaultTableModel) tblNumero.getModel();
        for (int i = 0; i < modelo.getRowCount(); i++) {
        modelo.removeRow(0);
        }
        String[] linha = new String[1];
        for (int i = 0; i < armarioList.size(); i++) {
            linha[0] = String.valueOf(armarioList.get(i).getNumArmario());
            modelo.addRow(linha);
         txtTot.setText(String.valueOf(modelo.getRowCount()));
        }


        tblNumero.setModel(modelo);
           }

public ArrayList<Armario> listarlivre() throws Exception {
        String sql = "select cod_armario from Armario,loc_armario where matricula != matri_aluno ";
        Connection conn = Conexao.getConexao();
        PreparedStatement pst = conn.prepareStatement(sql);
        ResultSet rs = pst.executeQuery();
        ArrayList<Armario> armarios = new ArrayList<Armario>();
        while (rs.next()) {
            Armario armario = new Armario();
            armario.setNumArmario(rs.getInt("cod_armario"));
            armarios.add(armario);
        }
        pst.close();
        conn.close();
        return armarios;
    }