[undertow]

looks to me that you are not sending the 2 CRLF characters. in the last add of your data arraylist i would suggest using "\r\n" and transmit with 'println' or, if you really want to be sure use "\r\n\r\n" and transmit that string with 'print' rather than 'println'. I hope that helps.

and dont forget to call flush() on the out object when you are done transmitting just to be sure the entire buffer is sent out.