Write a Linked list program using TCP Socket & Client Server

Server Side:

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

class node
{
 int data;
 node next;

 node()
 {
 next=null;
 }

 void setNext(node nxt)
 {
 next=nxt;
 }

 node getNext()
 {
 return next;
 }

 void setData(int d)
 {
 data=d;
 }

 int getData()
 {
 return data;
 }
}


class llist
{
 node head,tail;

 llist()
 {
 head=null;
 tail=null;
 }


 void insert(int d)
 {
 node tmp=new node();
 tmp.setData(d);
 if(head==null)
  head=tail=tmp;
 else
  {
  tail.setNext(tmp);
  tail=tmp;
  }
 }


 void delete()
 {
 node tmp;

 tmp=head;

 if(head==tail)
  head=tail=null;
 else
  {
  while(tmp.getNext()!=tail)
   tmp=tmp.getNext();

  tmp.setNext(null);
  tail=tmp;
  }
 }


 String display()
 {
 node tmp;
 String temp="";
 tmp=head;
        
 while(tmp!=null)           
  {
  temp=temp+"  "+tmp.getData();
  tmp=tmp.getNext();
  }
 return temp;
 }
}

public class Server
{
 public static void main(String arr[]) throws Exception
 {
 llist ls=new llist();

 ServerSocket ss=new ServerSocket(12345);
 Socket s=ss.accept();


 DataInputStream din=new DataInputStream(s.getInputStream());
 DataOutputStream dout=new DataOutputStream(s.getOutputStream());
 
 boolean val=true;
 while(val)
  {
  String str=din.readUTF();
  int ch=Integer.parseInt(str);

  switch(ch)
   {
   case 1: int t=Integer.parseInt(din.readUTF());
    ls.insert(t);
    break;
   case 2: ls.delete();
    break;
   case 3: String tmp=ls.display();
    dout.writeUTF("Current List: "+tmp);
    dout.flush();
    break;
   case 4: val=false;
    break;
   }
  } 
 }
}



Client Side:


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


public class Client
{
 public static void main(String arr[]) throws Exception
 {
 Socket s=new Socket("localhost",12345);

 DataInputStream din=new DataInputStream(s.getInputStream());
 DataOutputStream dout=new DataOutputStream(s.getOutputStream());
 Scanner sc=new Scanner(System.in);

 boolean val=true;
 while(val)
  {
  System.out.print("\n\nLINKED LIST Implementation \n1.Insert \n2.Delete\ n3.Display
 \n4.Exit \n\nYour choice: ");
  int ch=sc.nextInt();
  dout.writeUTF(""+ch);
  dout.flush();
  switch(ch)
   {
   case 1: System.out.print("\nData to be inserted: ");
    int t=sc.nextInt();
    dout.writeUTF(""+t);
    dout.flush();
    break;
   case 2: 
    break;
   case 3: String tmp=din.readUTF();
    System.out.println("\n"+tmp);
    break;
   case 4: val=false;
    break;
   }
  }
 }
}