I am using apache james 3

and when i am trying to send a e-mail although it seems that i send the e-mail i have this error at apache james:
INFO 00:51:21,527 | james.smtpserver | Id='882742847' User='' Connection established from
INFO 00:51:21,608 | james.smtpserver | Id='882742847' User='' Successfully spooled mail Mail1377726681596-357cbf87-73bd-4e3a-9ed9-c31a80268df6 from infos@lala.gr on localhost/ for [myemail@gmail.com]
INFO 00:51:21,626 | james.smtpserver | Id='882742847' User='' Connection closed for

INFO 00:51:36,720 | james.dnsservice | Couldn't resolve MX records for domain gmail.com.
INFO 00:51:36,721 | james.mailetcontext | Temporary problem looking up mail server for host: gmail.com
INFO 00:51:36,721 | james.mailetcontext | Temporary exception delivering mail (Mail1377726681596-357cbf87-73bd-4e3a-9ed9-c31a80268df6-to-gmail.com:
INFO 00:51:36,721 | james.mailetcontext | Storing message Mail1377726681596-357cbf87-73bd-4e3a-9ed9-c31a80268df6-to-gmail.com into outgoing after 0 retries

I do not knoe what i am doing wrong. Should i set a domain server? I want to test my project for now
Thank you very much

Couldn't resolve MX records for domain gmail.com.

this is an indication that the system was unable to figure out where the mail server(s) for gmail.com are located.

Does this system have its client DNS settings correctly configured? I dont know JSP very well, but I've never seen an instance where you need to specify the DNS servers to use in code. The system that is sending mail out uses its DNS settings to resolve hostnames to IP addresses.