In Java 8, the Streams is the new addition in the Java Collections API. It is the new method to process collections of objects. That is a different concept than the IO streams in the Java . Streams can be designed to work with Java lambda expressions.

The Below code will show you how you can return the Collection using the Stream.

import java.util.*; 
import java.util.stream.*; 
class Demo 
{ 
        public static void main(String ss[]) 
        { 
                List<String> list=new ArrayList<String>(); 
                list.add("babita"); 
                list.add("pooja"); 
                list.add("swati"); 
                list.add("nanda"); 
                list.add("nidhi"); 

                /* Returns the Stream from Collection*/ 
                Stream<String> stream=list.stream(); 


                /* Returns the Collections from Stream */ 
                List<String> names=stream.map(item->item.toUpperCase()).collect(Collectors.toList()); 
                System.out.println("Names  :"+names); 

        } 
} 

Hope this will help you :)