TreeSet provides an implementation of the Set interface that uses a tree for storage. Let’s see how to perform a few frequently used operations on the TreeSet. TreeSet does not allow to insert Heterogeneous objects. Adds the specified element to this set if it is not already present. extends E> c) It is used to build a new tree set that contains the elements of the collection c. The insertion of null values into a TreeSet throws. The TreeSet class consists various constructors which allow the possible creation of the TreeSet. In short, this constructor is used when any conversion is needed from any Collection object to TreeSet object. In short, this constructor is used to convert SortedSet object to the TreeSet Object. Apart from the methods inherited from its parent classes, TreeSet defines the following methods −. This method will return first element in TreeSet if TreeSet is not null else it will throw NoSuchElementException. TreeSet(Comparator): This constructor is used to build an empty TreeSet object in which elements will need an external specification of the sorting order. It will throw a, An object is said to be comparable if and only if the corresponding class implements. However, the insertion order is not retained in the TreeSet. 2. Adding Elements: In order to add an element to the TreeMap, we can use the add() method. A Tree is a non-linear data structure where data objects are organized in terms of hierarchical relationship. A Treeis a non-linear data structure where data objects are generally organized in terms of hierarchical relationship. code. 4. If we wish to create an empty TreeSet with the name ts with external sorting phenomenon, then, it can be created as: TreeSet ts = new TreeSet(Comparator comp); 3. For an empty tree-set, when trying to insert null as the first value, one will get NPE from JDK 7. Übersicht Collections. brightness_4 This method will add all elements of specified Collection to the set. TreeSet (Comparator