引用Java中的对象数组

Question

Before I get onto my question, I'd really like someone to give me specific advice because I've been searching for a long time now but can't seem to find out correct answer. I know it's basics but I am having issues. This is what I have in my code:

private Interface ClassName; //initializing class that implements interface

public Interface methodName () {
/*This is where I need to make arraylist of objects
of my class and return whole class as reference, maybe something like this:*/
List<Interface> listName = new ArrayList<>(perhaps needs number of objects added?);
listName.add(ClassName);

return ClassName; //or however this should be done

and I guess once I call method I could simply use listName.get(number of object);

Problem is, I would simply return list as reference, but my method requires me to only return class with said interface and I am not sure how to reference my class to that specific arraylist of objects and return it back in my method.

Thank you for your time. I'll try explaining in plain English. First of all, it's assigement so I can't change the ways methods are given. By the way, those were not actual variable names, just names to clarify what I am reffering to. This is explanation: /** * * Gets the {@link ISystemRegisters} object of the current computer system. * * * * @return Object representing the system registers. */ public ISystemRegisters getRegisters();

So I have class with different interface than ISystemRegisters and this method it in that is supposed to hold arrayList of objects (here registers) and then return object reference in which that array is, as I understood it.

Answer 1

If all you want to do is return your list from your method, then you should declare your method like this:

public List<Interface> methodName () { 
    ...
    return listName; // instead of returning ClassName
}

With the list as the return type.

Side notes :

• your first line is confusing, you're not initializing anything (as pointed out by @Lucas) but just declaring a variable (a field here) of type Interface with ClassName as name (which should be className instead).

• No, you don't need to specify the number of items at your list's creation. This is different from arrays.

• Your variable names are confusing, if you end with name , people will think the variable contains a name. They are likely to expect it that they are String s.