WHY THIS ERROR "java.net.SocketException: Connection reset" while running sever and client

package server_socket;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;


class Server_socket
{
       public static void main(String[] args) throws IOException
       {
           try
                {
                ServerSocket  sk = new ServerSocket (9999);
                Socket sock =sk .accept();
                BufferedReader br=new BufferedReader(new InputStreamReader(sock.getInputStream()));
                String temp=br.readLine();
                System.out.println("The mesage from client is::"+temp);
                PrintStream  pr=new PrintStream(sock.getOutputStream()); 
                String  str = "acknowledgement from server";
                pr.println(str);
                }
            catch (Exception ex)
                {
                }
        }
}	

package client_socket;

import java.io.*;
import java.net.Socket;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

 class client_socket
{
    public static void main(String[] args) throws IOException
    {
        Connection c = null;
        Statement stmt = null;
        try
        {
                    Socket sock = new Socket("10.176.24.48",9999);
                    PrintStream  pr=new PrintStream(sock.getOutputStream()); 
                    System.out.println("enter the message to be send to server");
                    BufferedReader  br=new  BufferedReader(new InputStreamReader(System.in));  
                    String temp = br.readLine();
                    pr.println(temp);	
                    BufferedReader  ed=new  BufferedReader(new InputStreamReader(sock.getInputStream())); 
                    String  st = ed.readLine();
                    System.out.println(st);
                    Class.forName("org.postgresql.Driver");
         c = DriverManager
            .getConnection("jdbc:postgresql://10.176.24.48:5432/postgres",
            "postgres", "");
         
         stmt = c.createStatement();
         String sql = "CREATE DATABASE TEST_DB_1 ENCODING 'UTF8'";
         stmt.executeUpdate(sql);
         stmt.close();
         c.close();
                    
        }
        catch(Exception ex)
        {
        System.err.println(ex.getClass().getName()+": "+ex.getMessage());
         System.exit(0);
      }
     
         System.out.println("DBcreated successfully");             

        
     
    }
}