How does UDP differ from TCP?

TCP is connection oriented protocol,mean it ensure that a packet is delivered and also set up a connection before sending data to destination source and destination exchange several control signal before sending data.If a packet is lost,TCP resend it. UDP does not establish any communication before sending data.It sends data and forget it.If a packet is lost,application using UDP cannot resend it.A example of UDP is voip,if a packet is lost,a part of conversation is also lost and can not be resend