ClientHandler.java

import java.net.*;
import java.io.*;
import java.util.*;

public class ClientHandler implements Runnable
{
    protected Socket s;
    String str;

    public ClientHandler(Socket st)
    {
        this.s = st;
    }

    @Override
    public void run()
    {
        try
        {
            // Scanner created.
            // We open a stream to to write into Scanner
            Scanner sc = new Scanner(s.getInputStream());

            // PrintWriter(Writer out, boolean autoFlush)
            PrintWriter pw = new PrintWriter(s.getOutputStream(), true);

            // Loop over InputStream to see what the client has requested
            while (sc.hasNext())
            {
                str = sc.nextLine();
                pw.println(reverseString(str));
            }

            sc.close();
            pw.close();
            s.close();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    public static String reverseString(String s)
    {
        StringBuffer sb = new StringBuffer(s);
        return (new String(sb.reverse()));
    }
}