tirei de um livro de redes de computadores - Kurose & Ross
DatagramSocketclientSocket=newDatagramSocket();InetAddressIPAdress=InetAddress.getByName("hostname");byte[]sendData=newbyte[1024];byte[]receiveData=newbyte[1024];Stringsentence=inFromUser.readLine();sendData=sentence.getBytes();// monta o pacote a ser enviadoDatagramPacketsendPacket=newDatagramPacket(sendData,sendData.length,IPAdress,9876);clientSocket.send(sendPacket);// envia pacoteDatagramPacketreceivePacket=newDatagramPacket(receiveData,receiveData.length);clientSocket.receive(receivePacket);