Java-具有不同对象类型的列表

Question

I have a Parent class. I made an array of 3 parent objects. I also have a child class. Is it possible that I can have 1 of those 3 array elements be a child object?

private ParentClass[] a = new ParentClass[3]

ParentClass a[] = {
     new ParentClass("0"),
     new ParentClass("1"),
     new ChildClass("2")
};

This works fine. But I'm wondering, is this the correct way of doing it or is there any easier/cleaner way?

New to java btw from C.

Answer 1

Alternatively you can do the following, List.of comes with Java 9. The returned list is immutable, immutable objects are very nice in a lot cases. Also in Java, we do Interface instance = new ImplementationClass() , for example List<Class> = new ArrayList<>() , ArrayList implements List interface

List<ParentClass> list = List.of( new ParentClass("0"), new ParentClass("1"), new ChildClass("2") );