How to correctly form multithreading?

Question

Java

Please tell me the best way to do it in my case. I want to parallelize tasks, but it turns out with only 1 thread. Constantly need to wait when I get the result d (future.get()). Is it possible to somehow make it so that the thread that is waiting for the result remains waiting, and the other thread continues to do its work further along the cycle?

List<Integer> index = new ArrayList<>();
        ///....///
        List<List<Integer>> dis = new ArrayList<>();
        for (int i = 0; i < links.size() - 1; i++) {
            if (index.get(i) == 0) {
                ..////...
                List<Integer> list = new ArrayList<>();
                for (int j = i + 1; j < links.size(); j++) {

                        URL oneURL = new URL(links.get(i));           
                        URL twoURL = new URL(links.get(j));
                        Task task = new Task(oneURL, twoURL);
                        ExecutorService executor = Executors.newFixedThreadPool(1);
                        Future<Double> future = executor.submit(task);
                        Double d = future.get();
                        executor.shutdown();
                        if (d > k) {
                            list.add(j);
                            index.set(j, 1);
                        }
                }
                dis.add(list);
            }
        }

Answer 1

In this form, it's all completely useless. Creating a thread is an expensive operation.
In order for this to work, you need to create an executor once, and submit different tasks to it. After the cycle, wait for them. Accordingly, the loop body should not depend on the result of the task execution.