将线程的结果相加：

import java.util.concurrent.*;

public class ThreadExample {
  public static void main(String[] args) throws InterruptedException, ExecutionException {
    ExecutorService executorService = Executors.newFixedThreadPool(10);

    int[] array = new int[1000];
    for (int i = 0; i < array.length; i++) {
      array[i] = i + 1;
    }

    int sum = 0;
    for (int i = 0; i < 10; i++) {
      int start = i * 100;
      int end = start + 100;
      Future future = executorService.submit(new AddThread(array, start, end));
      sum += future.get();
    }

    System.out.println("Sum: " + sum);

    executorService.shutdown();
  }
}

class AddThread implements Callable {
  private int[] array;
  private int start;
  private int end;

  public AddThread(int[] array, int start, int end) {
    this.array = array;
    this.start = start;
    this.end = end;
  }

  @Override
  public Integer call() throws Exception {
    int sum = 0;
    for (int i = start; i < end; i++) {
      sum += array[i];
    }
    return sum;
  }
}