Generics: Cannot convert from Collections.emptyList() to List<String>

Question

Why

public List<String> getList(){
    if (isMyListOKReady())
        return myList;
    return Collections.emptyList();
}

compiles well, but for

public List<String> getList(){
    return isMyListReady() ? myList : Collections.emptyList();
}

Eclipse says "Type mismatch: cannot convert from List<Object> to List<String>"?

Answer 1

You need to take care of type safety of empty list.

So return the empty list of string like this

public List<String> getList(){
    return isMyListReady() ? myList : Collections.<String>emptyList();
}

To be more specific, look you function is returning List<String>. So when you are using ternary operator then your condition should also return List<String>.

But in the case of Collections.emptyList() doesn't have it's type as List<String>. So Just need to specify the type of empty collection. So just use Collections.<String>emptyList().