How to make an ArrayList of Classes?

Question

How can I add a bunch of classes to an ArrayList and then later retrieve a Class (derived from, but not MyBaseClass) from the

Answer 1

Here is what I think you're asking for:

// get a list from somewhere
List list = new ArrayList();

// call list.add(...) a few times

// iterate over all the objects and check their sub class with "instanceof"
for (MyBaseClass item : list) {
    if (item instanceof MySubClass) {
        MySubClass subItem = (MySubClass) item;
        item.doThing();
    } else if (item instanceof OtherSubClass) {
        OtherSubClass subItem = (OtherSubClass) item;
        item.doThing();
    }
}

But if you find yourself needing to check if an object is the instance of a particular class, you're probably doing something wrong. Try creating an abstract method in MyBaseClass that can be implemented by each sub class in its own special way. Then, you can simplify the for loop to just this:

for (MyBaseClass item : list) {
    item.doThing();
}