Using Java8 Streams to create a list of objects from another two lists

Question

I have the following Java6 and Java8 code:

List lst1 = // a list of ObjectType1 objects
List lst2 = // a list of Object         


        

Answer 1

A Stream is tied to a given iterable/Collection so you can't really "iterate" two collections in parallel.

One workaround would be to create a stream of indexes but then it does not necessarily improve over the for loop. The stream version could look like:

List lst3 = IntStream.range(0, lst1.size())
         .mapToObj(i -> new ObjectType3(lst1.get(i).getAVal(), lst2.get(i).getAnotherVal()))
         .collect(toList());