Capacity of ArrayList [duplicate]

Answer 1

No you cannot ! Java ArrayList do not provide a way to access its current capacity.

You can only construct an ArrayList specifying an initial capacity using constructor ArrayList(int initialCapacity) or increase the capacity by calling ensureCapacity().

Answer 2

From the specification: "The capacity is the size of the array used to store the elements in the list. It is always at least as large as the list size. As elements are added to an ArrayList, its capacity grows automatically. The details of the growth policy are not specified beyond the fact that adding an element has constant amortized time cost."

So there's no way to tell what the current capacity is, nor how it grows.