Ftp 

Server Side:

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


class FtpServer
{
 public static void main(String args[]) throws Exception
 {
 ServerSocket ss=new ServerSocket(12345);
 Socket s=ss.accept();
 
 DataInputStream din=new DataInputStream(s.getInputStream());
 
 Scanner sc=new Scanner(System.in);
 System.out.print("Enter the target filename: ");
 String str=sc.nextLine();
 
 FileOutputStream fout=new FileOutputStream(str);
 while(true)
  {
  int i=Integer.parseInt(din.readUTF());
  if(i==-1)
   break;
  fout.write(i);
  }
 fout.close();
 din.close();
 s.close();
 ss.close();
 System.out.print("\n\nFile transfer successful...");  
 }
} 

Client Side:

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


class FtpClient
{
 public static void main(String args[]) throws Exception
 {
 Socket s=new Socket("localhost",12345);
 
 DataOutputStream dout =new DataOutputStream(s.getOutputStream());
 
 Scanner sc=new Scanner(System.in);
 System.out.print("Enter the source filename: ");
 String str=sc.nextLine();
 
 FileInputStream fin=new FileInputStream(str);
 while(true)
  {
  int i=fin.read();
  dout.writeUTF(""+i);
  dout.flush();
  if(i==-1)  
   break;
  }
 s.close();
 dout.close();
 fin.close();
 System.out.print("\n\nFile transfer successful...");  
 }
}