title: Add month with JodaTime?
body: <p>I'm trying add month with JodaTime. I have a payment plan with some months, example: one month, two month, three month and six month. </p>
  
  <p>When I add six month at DateTime doesn't work and return an exception.</p>
  
  <p>I'm trying this.</p>
  
  <pre><code>/** cria data vencimento matricula */    
      public void getDataVencimento(Integer dia, Integer planoPagamento){
          //monta data para JodaTime
          DateTime data = new DateTime();
          Integer ano = data.getYear();
          Integer mes = data.getMonthOfYear() + 6; //here 6 month
  
          //monta a data usando JodaTime
          DateTime dt = new DateTime(ano, mes, dia, 0, 0);        
          //convert o datetime para date
          Date dtVencimento = dt.toDate();    
          System.out.println(df.format(dtVencimento));
          //retorna a proxima data vencimento
         // return dtVencimento;
      }
  
  /** exception */
  Exception in thread "AWT-EventQueue-0" org.joda.time.IllegalFieldValueException: Value 14 for monthOfYear must be in the range [1,12]
  
  
  /** I did this and now works */
  /** cria data vencimento */    
      public Date getDataVencimento(Integer dia, Integer planoPagamento){
          //monta data para JodaTime
          DateTime data = DateTime.now();//pega data de hoje        
          DateTime d = data.plusMonths(planoPagamento);//adiciona plano de pagamento
  
          //cria data de vencimento
          DateTime vencimento = new DateTime(d.getYear(), d.getMonthOfYear(), dia, 0, 0);
          //convert o datetime para date
          Date dtVencimento = vencimento.toDate();            
          //retorna a proxima data vencimento
          return dtVencimento;
      }
  </code></pre>
  
  <p>How to I can solve this problem ?</p>