Simple echo server and client using TCP/IP

Implement a simple echo server and client which uses TCP/IP for the communication. The client after 

establishing the connection, sends server a message which the latter echoes (i.e., the server prints out the 

message).The server should be capable of handling multiple clients. The clients need to know the address 

of server(IP address and port) it wants to communicate to beforehand.

Your client-server should not be a standalone pair of program. Server should be able to accept connections

from other clients and echo their message. You should be able to contact other servers and send a message 

to be echoed.

This project implements a simple echo server and client which uses TCP/IP for communication.

Programming language used: JAVA

How to compile : javac echoserver.java

To run : java echoserver

Do the same for echoclient.java file

To test :

1. Compile and run echoserver.java
2. Compile and run echoclient.java
3. Input the hostname and port number

You can access the project here
github repository
EXPLANATION

echoserver.java :
........................
As the Server should support multiple clients, we extend our java class to use thread concept.

public class echoserver extends Thread

Get port number to use as user input. The server socket waits forrequests to come in over the network. 

To establish the socket connection between the client and the server, we use

new echoserver (sSocket.accept());

Accept() is a blocking call. If the connection is accepted by the server, it reads a line from client's 

input stream. Server echoes the message and write to client's outputstream using PrintWriter

PrintWriter out = new PrintWriter(cSocket.getOutputStream(), true);
BufferedReader in = new BufferedReader(new InputStreamReader

(cSocket.getInputStream()));

Continuously read message from client

while ((clientmsg = in.readLine()) != null)
{
System.out.println ("Message from client: " + clientmsg);
out.println(clientmsg);
}

The socket and streams are closed after the use.

out.close();
in.close();
cSocket.close();

echoclient.java :
........................
Read the hostname and port number to connect.

Scanner sc= new Scanner(System.in);
BufferedReader s=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the IP address");
String ip=s.readLine();
System.out.println("Enter Port No. to connect");
int port =sc.nextInt();

Create a socket to connect to server

Socket clientsoc =null;

Write to the PrintWriter to send the message to server

out = new PrintWriter(clientsoc.getOutputStream(), true);

The second parameter of PrintWriter() is boolean (autoflush). Read server response from socket's

inputstream.

in = new BufferedReader(new InputStreamReader(clientsoc.getInputStream()));

On completion, close the open socket.

clientsoc.close();