Thread: Collections vs. Objects

Hi,

I am new to the forum and new to collections. I am reading up on the basics of collections and trying to understand the difference between collections and objects. Firstly, are collections objects? My understanding is that collections group together similar elements: don't objects/classes do this as well? Could anything done by a collection then just be done by designing a custom class/object? I am guessing the Collections might be more optimized than doing so; but is efficiency the only reason to use collections rather than designing your own data-type/class/object?

Thanks very much. (Feel free to link me to existing resources about this rather than writing an answer if those are available..)

-Dan

Collection is data structure which we can insert different objects in it. For example ArrayList is the collections class which we can insert here different kinds of objects in it. But Object is the one which is single. It can be any kind of object. Simply we say Object is a singular, where Collections are the many kinds of objects. I hope it is usefull answer.

My understanding is that collections group together similar elements: don't objects/classes do this as well? Could anything done by a collection then just be done by designing a custom class/object?

Some collections are required to contain data elements of the same type, so from that you could say the elements are similar. But classes are designed to describe things or perform functions that may contain many dissimilar elements, like several different data types. In that way, collections can be very different from other classes. And, no, I don't think ANYTHING can be done by an existing collection that COULD BE DONE by a custom class.