Search using Thread

Question

I am looking for files using threads, the code I developed looks for the right file , but it turns out that it does not finish the execution when it finds , or if it does not find it continues running.

import java.io.File;
import java.util.Scanner;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import javax.swing.JOptionPane;

public class ProcuraArquivoThreadPool implements Runnable{

private static boolean achou;
private File pasta;
private String arquivo;
private Executor pool;

public ProcuraArquivoThreadPool(File pasta, String arquivo, Executor pool) {
    this.pasta = pasta;
    this.arquivo = arquivo;
    this.pool = pool;
}
public static void procura(String pasta, String arquivo, Executor pool) {
    achou = false;
    pool.execute(new ProcuraArquivoThreadPool(new File(pasta), arquivo, pool));

}

public void run() {
    if(achou){
        return;
    }

    for(File f : pasta.listFiles()){
        if(achou){
            break;
        } else if(f.isDirectory()){
            pool.execute(new ProcuraArquivoThreadPool (f, arquivo, pool));                               
        } else if(f.getName().equalsIgnoreCase(arquivo)){
            System.out.println("Achei: " + f.getPath());
            achou = true;
            break;
        }
    }
}

public static void main (String[] args){
    Scanner teclado = new Scanner(System.in);

    //System.out.println("Digite o caminho da Pasta");
    //String pasta = teclado.nextLine();
    System.out.println("Digite o arquivo a ser procurado");
    String arquivo = teclado.nextLine();

            String pasta = "C:/";

            System.out.println("Procurando......");

    ScheduledExecutorService threadpool = Executors.newScheduledThreadPool(4);

    procura(pasta, arquivo,threadpool);
}
}