Question

Suppose I have an object that looks like:

public class Obj {
String foo;
String bar;
}

If I create an arraylist of type Obj and populate it, is there a way I can return a list of all the objects in the array’s foo attribute from the ArrayList?

EDIT: I should have been more clear, I did not want to do this via iteration

Answer 1

You’ll have to iterate through your List<Obj> and collate the foo entries into a new List

e.g.

List<String> foos = new ArrayList<String>();
for (Obj obj : objs) {
  foos.add(obj.foo)
}

or for Java 8 and beyond, use streams thus:

objs.stream().map(o -> o.foo).collect(toList());