Method name | Meaning
----- | -----
boolean add(E element) | inserts a new element into the Collection and returns whether it was successful.
addAll(Collection c) | This method adds all the elements in the given collection to this collection.
boolean remove(Object object) | removes a single matching value in the Collection and returns whether it was successful.
boolean isEmpty() | checks if the Collection is empty
int size() | checks the size the Collection
void clear() | discards all elements of the Collection.
boolean contains(Object object) | checks if a certain value is in the Collection.
containsAll(Collection c) | This method returns true if the collection contains all of the elements in the given collection.