Supertype: 
Object
		
		
		
Table 9. Operations
| Return type | Name | Description | 
|---|---|---|
| Boolean | contains(Object) | returns true if this collection contains the specified object. otherwise false. returns this Collection. | 
| List | toList() | converts this collection to List | 
| Set | toSet() | converts this collection to Set | 
| List | flatten() | returns a flattened List. | 
| Set | intersect(Collection) | returns a new Set, containing only the elements contained in this and the specified Collection | 
| String | toString(String) | concatenates each contained element (using toString()), separated by the specified String. | 
| Collection | removeAll(Collection) | removes all elements contained in the specified collection from this Collection if contained (modifies it!). returns this Collection. | 
| Collection | remove(Object) | removes the specified element from this Collection if contained (modifies it!). returns this Collection. | 
| Set | without(Collection) | returns a new Set, containing all elements from this Collection without the elements from specified Collection | 
| Collection | addAll(Collection) | adds all elements to the Collection (modifies it!). returns this Collection. | 
| Collection | add(Object) | adds an element to the Collection (modifies it!). returns this Collection. | 
| Set | union(Collection) | returns a new Set, containing all elements from this and the specified Collection | 
| Boolean | containsAll(Collection) | returns true if this collection contains each element contained in the specified collection. otherwise false. returns this Collection. |