combine two list of pojos into another list of pojo on the basis of specific value using java 8

Question

I am trying to enhance my current code using java 8

I have two list of pojos

    class A{
    long id;
    String name;
    Sting age;
// getters setters
    }

    class B{
    long id;
    String address;
    String city;
// getters setters
    }

required class:

    class C{
    long id;
    String name;
    Sting age;
    String address;
    String city;
// getters setters
    }

i have list<A> and List<B>, and require final List<C>. I have completed this using for loops and everything. but i now want to streamline in using java 8 functionalitis.

Any help is very much appreciated.

EDIT

 List<C> cList=new ArrayList<>();
    C obj=new C();
    for(A aa: aList){
    C obj=new C();
     obj.setId(a.getId);
     obj.setName(a.getName);
     obj.setAge(a.getAge);
       for(B bb: bList){
         if(aa.getId==bb.getId(){
           obj.setAddress(bb.setAddress);
           obj.setCity(bb.setCity);
          }
       } 
       cList.add(obj); 
    }

Answer 1

if you want just transfer your code to streams, you can:

List<C> collect = aList.stream()
        .map(a -> {
            C obj = new C();
            obj.setId(a.getId());
            obj.setName(a.getName());
            obj.setAge(a.getAge());
            bList.stream()
                    .filter(b -> a.getId() == b.getId())
                    .findFirst()
                    .ifPresent(b -> {
                        obj.setAddress(b.getAddress());
                        obj.setCity(b.getCity());
                    });
            return obj;
        }).collect(toList());

But it will be better to introduce map for bList and use it as a lookup latter.

Map<Long, B> map = bList.stream()
        .collect(Collectors.toMap(B::getId, b -> b));

List<C> collect = aList.stream()
        .map(a -> {
            C obj = new C();
            obj.setId(a.getId());
            obj.setName(a.getName());
            obj.setAge(a.getAge());
            if (map.containsKey(a.getId())) {
                B b = map.get(a.getId());
                obj.setAddress(b.getAddress());
                obj.setCity(b.getCity());
            }
            return obj;
        }).collect(toList());