How to make 2 threads work synchronization need someone who can solve the question of edit my code ?

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Java

you are going to use the semaphores for process synchronization. Therefore, you are asked to develop a consumer and producer multithreaded program.
Let’s assume, that we have a thread (producer, we will call it producer_thread) reading data (positive integer numbers) from the keyboard, entered by a user to be stored in an array (dynamic array). (Assume that the array can hold all numbers entered without overflow.)

Another thread (consumer, we will call it consumer_thread) should read data from the array and write them into a file. This thread should run concurrently with the producer (producer_thread).
Your program should make sure that the consumer_thread can read from the array only after the producer_thread has stored new data. Both threads will stop when the user enters a negative number.


Thereafter, another thread (testing_thread) should start reading the array data as well as the file data and display them on the screen in order to verify if the consumer and producer have worked in a correctly synchronized fashion. This thread should not be synchronized with other threads, it useful for testing that consumer thread is synchronized with produce thread.

What I have tried:

package multithreaded;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Scanner;
import java.util.concurrent.Semaphore;
import java.util.logging.Level;
import java.util.logging.Logger;



public class MultiThreaded {

    public static void main(String[] args) throws InterruptedException {
        
       Thread t1 =new Thread(new Runnable(){
           
        @Override
        public  void run(){
        try{
            producer_thread();
        }
        catch(InterruptedException e){
            e.printStackTrace();
        }
 
        }
        });
         Thread t2 =new Thread(new Runnable(){
        @Override
        public  void run(){
        try{ 
            consumer_thread();
        }
          catch (IOException ex) {   
                Logger.getLogger(MultiThreaded.class.getName()).log(Level.SEVERE, null, ex);
            }
        
        
        
        }
        });
         Thread t3 =new Thread(new Runnable(){
        @Override
        public void run(){
        try{ 
            testing_thread();
        }
          catch (IOException ex) {   
                Logger.getLogger(MultiThreaded.class.getName()).log(Level.SEVERE, null, ex);
            } catch (InterruptedException ex) {
                Logger.getLogger(MultiThreaded.class.getName()).log(Level.SEVERE, null, ex);
            }
        
        
        
        }
        });
       t1.start();
       t2.start();
       t3.start();
    }
    private static Semaphore sem =new Semaphore(1);

    private static ArrayList<Double> FromUser = new ArrayList<>();
    private static void producer_thread() throws InterruptedException{
     sem.acquire();
     Scanner input = new Scanner(System.in);
     System.out.print("Enter the numbers: ");
     Double s=input.nextDouble(); 
     while(s>=0)
     {
        FromUser.add(s);
         s=input.nextDouble(); 
     }
     sem.release();
     
      
    }
  private static void consumer_thread() throws IOException {
        try {
            sem.acquire();
        } catch (InterruptedException ex) {
            Logger.getLogger(MultiThreaded.class.getName()).log(Level.SEVERE, null, ex);
        }
            PrintWriter outputWriter = new PrintWriter("Em.txt");
            for (int i = 0; i <FromUser.size(); i++) {
                outputWriter.println(FromUser.get(i)+"");
            }
            
            outputWriter.close();
        sem.release();
        } 
private static void testing_thread() throws InterruptedException, FileNotFoundException{
    try {
            sem.acquire();
        } catch (InterruptedException ex) {
            Logger.getLogger(MultiThreaded.class.getName()).log(Level.SEVERE, null, ex);
        }
    
    System.out.println("the stored numbers in the ArrayList:"+FromUser);
    Scanner file=new Scanner(new File("Em.txt"));
     System.out.println("the stored numbers in the Text file:");
    while(file.hasNextLine()){
    String data=file.nextLine();
    System.out.println(data);
    }
   
    sem.release();

    }
     }