Distributed application using RMI for Remote Computation

Aim: Design a distributed application using RMI for remote computation where client submits two strings to the server and server returns the concatenation of the given strings.

Requirement:  Eclipse - http://www.professionalcipher.com/2018/03/installation-of-eclipse-on-ubuntu.html

How to Run program in Eclipse:  

1. First run the Server.java 
2. Then Client.java

Code: 

1. Create a class named Server.java

import java.sql.*;
import java.sql.Connection;
import java.rmi.*;
import java.rmi.Naming.*;
import java.rmi.server.*;
import java.rmi.registry.*;
import java.util.Vector;

interface DBInterface extends Remote 
{
 public String input(String name1, String name2) throws RemoteException;
}
public class Server extends UnicastRemoteObject implements DBInterface 
{
 int flag = 0, n, i, j;
 String name3;
 ResultSet r;
 public Server() throws RemoteException 
 {
  try 
  {
   System.out.println("Initializing Server\nServer Ready");
  } catch (Exception e) 
  {
   System.out.println("ERROR: " + e.getMessage());
  }
 }
 public static void main(String[] args) 
 {
  try 
  {
   Server rs = new Server();
   java.rmi.registry.LocateRegistry.createRegistry(1030).rebind(
     "DBServ", rs);
  } 
  catch (Exception e) 
  {
   System.out.println("ERROR: " + e.getMessage());
  }
 }
 public String input(String name1, String name2) 
 {
  try 
  {
   name3 = name1.concat(name2);
  } 
  catch (Exception e) 
  {
   System.out.println("ERROR: " + e.getMessage());
  }
  return name3;
 }
}

2. Create a class named Client.java

import java.sql.*;
import java.rmi.*;
import java.io.*;
import java.util.*;
import java.util.Vector.*;
import java.lang.*;
import java.rmi.registry.*;

public class Client 
{
 static String name1, name2, name3;

 public static void main(String args[])
 {
   Client c=new Client();
   BufferedReader b = new BufferedReader(new
   InputStreamReader(System.in));
   int ch;
   try 
   {
     Registry r1 = LocateRegistry.getRegistry ( "localhost", 1030);
     DBInterface DI=(DBInterface)r1.lookup("DBServ");
     do
     {
       System.out.println("1.send input stings\n2.Display \n concatenated string \nEnter ur choice");
       ch= Integer.parseInt(b.readLine());
       switch(ch)
       {
          case 1:
          System.out.println(" \n Enter first string:");
          name1=b.readLine();
          System.out.println(" \n Enter second string:");
          name2=b.readLine();
          name3=DI.input(name1,name2);
          break;
          case 2:
          //display
          System.out.println("\nConcatenated String is : ");
          int i=0;
          System.out.println(" "+name3 +"");
          break;
       }
     }while(ch>0);
   }
   catch (Exception e)
   {
     // System.out.println("ERROR: " +e.getMessage());
   }
 }
}