java - Can we make the order of one list based on other? -

i have 2 array lists list1 , list2 , want list2 order order of list1. there way this? in 1 list got top performing emploee database , list 2 got database second time using top performing employee ids using "in" clause.

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list<long> list1 = new arraylist<long>(); list1.add(5645); list1.add(2312); list1.add(7845); list1.add(1212); 

and other list of object type:

list<employee> list2 = new arraylist<employee>(); list2.add(new employee(1212, "a")); list2.add(new employee(2312, "v")); list2.add(new employee(5645, "d")); list2.add(new employee(7845, "t")); 

where list1 shows employee id of top 4;

and got employee detail data base using id , got list2.

now want make order of list2 list1 show on html page.

just iterate list1 , each item find matching element in list2. no need sort.

list<employee> sortedlist = new arraylist<>(); (long id : list1) {     employee match = collectionutils.find(list2, e -> e.id.equals(id));     // cannot sort, if list2 not contain id, or put rule case     assert match != null;      sortedlist.add(match); } 

this uses apache commons collections's collectionutils.

or, better performance, build map first:

map<long, employee> lookupmap = new hashmap<>(list2.size()); (employee e : list2)     lookupmap.put(e.id, e);  list<employee> sortedlist = new arraylist<>(list2.size()); (long id : list1)     sortedlist.add(lookupmap.get(id));