Implementation of HTTP socket for File Upload and Download

In the below code the client uploads the image to the server, and for downloading the code is just the inverse and the code is executed as vice versa.

Here the image is transfered for instance the transfering file can be of any format based on it the code varies a little bit.

 Server.java:

 import java.net.*;
import java.io.*;
import java.awt.image.*;
 import javax.imageio.*;
import javax.swing.*;
class Server {
public static void main(String args[]) throws Exception{
    ServerSocket server=null;
    Socket socket;
    server=new ServerSocket(4000);
    System.out.println("Server Waiting for image");
    socket=server.accept(); System.out.println("Client connected.");
    InputStream in =    socket.getInputStream();
    DataInputStream dis = new DataInputStream(in);
    int len = dis.readInt();
    System.out.println("Image Size: " + len/1024 + "KB");
    byte[] data = new byte[len];
    dis.readFully(data);
    dis.close();
    in.close();
    InputStream ian = new ByteArrayInputStream(data);
    BufferedImage bImage = ImageIO.read(ian);
    File outputfile = new File("bicycle1.png");
    ImageIO.write(bImage, "png", outputfile);
}
}

Client.java:

import javax.swing.*;
import java.net.*;
import java.awt.image.*;
import javax.imageio.*;
import java.io.*;
public class Client{
public static void main(String args[]) throws Exception{
    Socket soc;
    BufferedImage img = null;
    soc=new Socket("localhost",4000);
    System.out.println("Client is running. ");
     try {
        System.out.println("Reading image from disk. ");
        img = ImageIO.read(new File("bicycle.jpg"));
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageIO.write(img, "jpg", baos);
        baos.flush();
        byte[]  bytes = baos.toByteArray();
        baos.close();
        System.out.println("Sending image  ");
        OutputStream out = soc.getOutputStream();
        DataOutputStream dos = new DataOutputStream(out);
        dos.writeInt(bytes.length);
        dos.write(bytes, 0, bytes.length);
        System.out.println("Image sent ");
        dos.close();
        out.close();
    }catch (Exception e) {
        System.out.println("Exception: " + e.getMessage());
        soc.close();
    }
    soc.close();
}
}

Output: