code: public Object getAsObject(FacesContext facesContext, UIComponent uiComponent, String value)
      {
          if (facesContext == null)
          {
              throw new NullPointerException("facesContext");
          }
          if (uiComponent == null)
          {
              throw new NullPointerException("uiComponent");
          }
  
          if (value != null)
          {
              value = value.trim();
              if (value.length() > 0)
              {
                  try
                  {
                      value = fixLocale(facesContext, value);
                      return this.stringToDouble(value);
                  }
                  catch (NumberFormatException e)
                  {
                      throw new ConverterException(_MessageUtils.getErrorMessage(facesContext,
                                     DOUBLE_ID,
                                     new Object[]{value,"4214",_MessageUtils.getLabel(facesContext, uiComponent)}), e);
                  }
  
              }
          }
          return null;
      }
docs: METHODS