| Name | Description | Type | Package | Framework |
| AbstractNavigableSetDecorator | Decorates another NavigableSet to provide additional behaviour. | Class | org.apache.commons.collections4.set | Apache Commons |
| AbstractSerializableSetDecorator | Serializable subclass of AbstractSetDecorator. | Class | org.apache.commons.collections4.set | Apache Commons |
| AbstractSetDecorator | Decorates another Set to provide additional behaviour. | Class | org.apache.commons.collections4.set | Apache Commons |
| AbstractSortedSetDecorator | Decorates another SortedSet to provide additional behaviour. | Class | org.apache.commons.collections4.set | Apache Commons |
| CompositeSet | Decorates a set of other sets to provide a single unified view. | Class | org.apache.commons.collections4.set | Apache Commons |
| CompositeSet .SetMutator | Define callbacks for mutation operations. | Interface | org.apache.commons.collections4.set.CompositeSet | Apache Commons |
| ListOrderedSet | Decorates another Set to ensure that the order of addition is retained and used by the iterator. | Class | org.apache.commons.collections4.set | Apache Commons |
| MapBackedSet | Decorates a Map to obtain Set behaviour. | Class | org.apache.commons.collections4.set | Apache Commons |
| PredicatedNavigableSet | Decorates another NavigableSet to validate that all additions match a specified predicate. | Class | org.apache.commons.collections4.set | Apache Commons |
| PredicatedSet | Decorates another Set to validate that all additions match a specified predicate. | Class | org.apache.commons.collections4.set | Apache Commons |
| PredicatedSortedSet | Decorates another SortedSet to validate that all additions match a specified predicate. | Class | org.apache.commons.collections4.set | Apache Commons |
| SetUtils | Provides utility methods and decorators for Set and SortedSet instances. | Class | org.apache.commons.collections4 | Apache Commons |
| SetUtils .SetView | An unmodifiable view of a set that may be backed by other sets. | Class | org.apache.commons.collections4.SetUtils | Apache Commons |
| SetValuedMap | Defines a map that holds a set of values against each key. | Interface | org.apache.commons.collections4 | Apache Commons |
| TransformedNavigableSet | Decorates another NavigableSet to transform objects that are added. | Class | org.apache.commons.collections4.set | Apache Commons |
| TransformedSet | Decorates another Set to transform objects that are added. | Class | org.apache.commons.collections4.set | Apache Commons |
| TransformedSortedSet | Decorates another SortedSet to transform objects that are added. | Class | org.apache.commons.collections4.set | Apache Commons |
| UnmodifiableNavigableSet | Decorates another NavigableSet to ensure it can't be altered. | Class | org.apache.commons.collections4.set | Apache Commons |
| UnmodifiableSet | Decorates another Set to ensure it can't be altered. | Class | org.apache.commons.collections4.set | Apache Commons |
| UnmodifiableSortedSet | Decorates another SortedSet to ensure it can't be altered. | Class | org.apache.commons.collections4.set | Apache Commons |