List<String> list=new ArrayList();
list.add("1");
list.add("2");
list.add("3");
list.add("4");
list.add("5");
List<Object> result = new ArrayList();
CompletableFuture<List<Object>>[] futures = new CompletableFuture[list.size()];
for (int i = 0; i < list.size(); i++) {
futures[i] = CompletableFuture.supplyAsync(() -> {
return getSomething(list.get(i));
});
}
CompletableFuture.allOf(futures).join();
for (int o = 0; o < futures.length; o++) {
CompletableFuture<List<Object>> future = futures[o];
List<Object> datas = future.join();
result.addAll(datas);
}