TCP vs UDP

TCP:
Need to establish a connection before starting data transfer (Handshake)reliable, slow, heavy header:
Data order is guaranteedEx: HTTP, SMTP, FTP, Telnet, HTTPs,
uses: most of the finance domains uses TCP

UDP:
No handshaking required
fast, small header, unreliable
Ex: DHCP, DNS
uses: mostly used in Video streaming, online gamings

more:
http://javarevisited.blogspot.in/2014/07/9-difference-between-tcp-and-udp-protocol.html