Implementation of Transmission Control Protocol (TCP) by File Transfer Program

This is java program implementing TCP by transferring a file between the client and sever by using the localhost a address where any address can be placed even remote addresses are supported with certain file permissions.

FileTransferServer.java:

 import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

public class FileTransferServer {
   
    public static void main(String[] args) throws Exception {

        //Initialize Sockets
        ServerSocket ssock = new ServerSocket(5000);
        Socket socket = ssock.accept();
       
        //The InetAddress specification
        InetAddress IA = InetAddress.getByName("localhost");
       
        //Specify the file
        File file = new File("images.png");
        FileInputStream fis = new FileInputStream(file);
        BufferedInputStream bis = new BufferedInputStream(fis);
         
        //Get socket's output stream
        OutputStream os = socket.getOutputStream();
               
        //Read File Contents into contents array
        byte[] contents;
        long fileLength = file.length();
        long current = 0;
        
        long start = System.nanoTime();
        while(current!=fileLength){
            int size = 10000;
            if(fileLength - current >= size)
                current += size;   
            else{
                size = (int)(fileLength - current);
                current = fileLength;
            }
            contents = new byte[size];
            bis.read(contents, 0, size);
            os.write(contents);
            System.out.print("Sending file ...  /images.png\n "+(current*100)/fileLength+"% complete!");
        }  
       
        os.flush();
        //File transfer done. Close the socket connection!
        socket.close();
        ssock.close();
        System.out.println("File sent succesfully!");
    }
}

 FileTransferClient.java:

import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.InetAddress;
import java.net.Socket;


public class FileTransferClient {
   
    public static void main(String[] args) throws Exception{
       
        //Initialize socket
        Socket socket = new Socket(InetAddress.getByName("localhost"), 5000);
        byte[] contents = new byte[10000];
       
        //Initialize the FileOutputStream to the output file's full path.
        FileOutputStream fos = new FileOutputStream("image.png");
    System.out.println("Saved as: /image.png");
        BufferedOutputStream bos = new BufferedOutputStream(fos);
        InputStream is = socket.getInputStream();
       
        //No of bytes read in one read() call
        int bytesRead = 0;
       
        while((bytesRead=is.read(contents))!=-1)
            bos.write(contents, 0, bytesRead);
       
        bos.flush();
        socket.close();
       
        System.out.println("File saved successfully!");
    }
}

Output: