angular read element from html by atribute name

CompletableFuture<Long> completableFuture = CompletableFuture.supplyAsync(() -> factorial(number));
while (!completableFuture.isDone()) {
    System.out.println("CompletableFuture is not finished yet...");
}
long result = completableFuture.get();
ExecutorService threadpool = Executors.newCachedThreadPool();
Future<Long> futureTask = threadpool.submit(() -> factorial(number));
 
while (!futureTask.isDone()) {
    System.out.println("FutureTask is not finished yet..."); 
} 
long result = futureTask.get(); 
 
threadpool.shutdown();
int number = 20;
Thread newThread = new Thread(() -> {
    System.out.println("Factorial of " + number + " is: " + factorial(number));
});
newThread.start();