java - joining results after making parallel calls using spring async -

i'm using spring @async make parallel calls same method/backend. there clean way join results in list? pseudo code came make calls/merge result, i'm not sure it's cleanest way.

list<future<string>> futurestringlist = new arraylist<future<string>>(); for(each backend call){            future<string> futurestring = backend.retrieve();            futurestringlist.add(futurestring); }   list<string> actualstringlist = new arraylist<string>();      while(!futurestringlist.isempty()){            for(future<string> futurestring: futurestringlist){                           if(futurestring.isdone()){                                          actualstringlist.add(futurestring.get());                                          futurestringlist.remove(futurestring);                           }            }     } 

future.get() blocking call, can loop on future list , know that, @ end of loop, futures finished.

list<future<string>> futurestringlist = new arraylist<future<string>>(); for(each backend call){     future<string> futurestring = backend.retrieve();     futurestringlist.add(futurestring); }  list<string> actualstringlist = new arraylist<string>(); (future<string> stringfuture : futurestringlist) {   actualstringlist.add(stringfuture.get()); // blocking call }  // strings retrieved @ point