Remove elements from a collection

boolean remove(Object o)

Removes a single instance of the specified element from this collection, if it is present (optional operation).

boolean removeAll(Collection<?> c)

Removes all of this collection's elements that are also contained in the specified collection (optional operation).

boolean retainAll(Collection<?> c)

Retains only the elements in this collection that are contained in the specified collection (optional operation).

1. Collection interface
2. Add elements to a collection
3. Is it contained in the collection
4. Compare two collections
5. Remove elements from a collection
6. Convert collection to Array
7. Get the size of a Collection
8. Is a collection empty
9. Clear a collection
10. Get the iterator() from a collection