Table 1


Methods for the collection class.

Boolean add (Object) Ensures that the collection contains the argument. Returns false if it doesn't add the argument.1
Boolen addAll (Collection) Adds all the elements in the argument. Returns true if any elements were added.1
void clear () Removes all the elements in the collection.
Boolean contains (Object) True if the collection contains the argument.
Boolean containsAll (Collection) True if the collection contains all the elements in the argument.
Boolean isEmpty () True if the collection has no elements.
Iterator iterator () Returns an Iterator that you can use to move through the elements in the collection.
Boolean remove (Object) If the argument is in the collection, one instance of that element is removed. Returns true if a removal occurred.1
Boolean removeAll (Collection) Removes all the elements that are contained in the argument. Returns true if any removals occurred.1
Boolean retainAll (Collection) Retains only elements that are contained in the argument (an "intersection" from set theory). Returns true if any changes occurred.1
int size () Returns the number of elements in the collection.
Object [] toArray () Returns an array containing all the elements in the collection.
1This is an "optional" method, which means it might not be implemented by a particular collection. If not, that method throws an UnsupportedOperationException