Is it possible to create a collection of different class types, so that an object can be later checked to see if it is an object of any of these classes in the collection? something like: for(Class... More on stackoverflow.com

Collections are just data structures. The classes that are part of the collections API are not Java-specific structures, and exist in many languages. Here's a basic rundown of the ones that you will use 99% of the time: Legend: parent class/interface (child classes) List (ArrayList): Essentially a resizable array that you can add elements to without having to specify an index. Set (HashSet): A collection of unique elements. Does not remember insertion order (unlike an ArrayList), but very quick to search for elements. Map (HashMap): A collection of key-value pairs with unique keys. LinkedList: A series of nodes that are linked to each other to allow for very fast insertion and deletion of elements. Commonly used when a stack or queue is needed. PriorityQueue: A queue that automatically orders newly added elements. Here's some additional reading if you want. More on reddit.com

If all you need is a standard collection of objects, and the Collections API has all the functionality you need for it already implemented, then you probably stick with the Collections API (or some other API; chances are there's already an implementation out there for what you need to do). Probably the only reason you'd need to extend Collection or one of its subclasses is to add functionality or do something different than what they can do. For treating n-dice as a single object, you do probably want to make a Dice object that wraps around several Die objects so that you won't have to be iterating over List or Set everywhere, which means you can add your own functionality and semantics to make your life easier: dice.sum() {} // rolls the dice and returns the sum of the rolls dice.countRollsGreaterThan(int lowerBound) {} // calls die.roll() on all of the Die objects and returns a count of how many rolled a number larger than the lowerBound // and so on More on reddit.com

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