{"id":980,"date":"2016-03-01T06:02:47","date_gmt":"2016-03-01T06:02:47","guid":{"rendered":"http:\/\/abhiandroid.com\/java\/?p=980"},"modified":"2016-03-01T06:07:43","modified_gmt":"2016-03-01T06:07:43","slug":"treeset-methods-java-examples","status":"publish","type":"post","link":"https:\/\/abhiandroid.com\/java\/treeset-methods-java-examples.html","title":{"rendered":"TreeSet Methods In Java With Examples"},"content":{"rendered":"<p>TreeSet is a type of Collection, that implements Set Interface. In TreeSet all the values are stored in there natural order, like all integer values are stored in ascending order and strings are stored according to Dictionary values.\u00a0Apart from adding this functionality of maintaining natural ordering, TreeSet do not allow null values.<\/p>\n<hr \/>\n<h4><strong><span style=\"color: #008000;\">TreeSet Methods in JAVA:<\/span><\/strong><\/h4>\n<p>Let us discuss all the TreeSet\u00a0methods one by one with Examples in Java.<\/p>\n<p><span style=\"color: #008000;\"><strong>1. boolean add(Object o):<\/strong><\/span><\/p>\n<p>This methods adds element in the object, which will automatically stores all the elements in increasing order, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;String&gt;treeSetObject2 = new TreeSet&lt;String&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject2.add(\"B\");\r\n\r\n  treeSetObject2.add(\"C\");\r\n\r\n  treeSetObject2.add(\"A\");\r\n\r\n  treeSetObject2.add(\"D\");\r\n\r\n  treeSetObject2.add(\"A\");\r\n\r\n  System.out.println(\"Values in TreeSet object 1: \" +treeSetObject1);\r\n\r\n  System.out.println(\"Values in TreeSet object 2: \u00a0\" +treeSetObject2);\r\n\r\n  }\r\n\r\n}\r\n<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in TreeSet object 1: [1, 2, 3, 5]\r\n\r\nValues in TreeSet object 2: [A, B, C, D]<\/pre>\n<p><span style=\"color: #008000;\"><strong>2. boolean addAll(Collection c):<\/strong><\/span><\/p>\n<p>This method adds all the elements of one object to another , as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject2 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject2.add(9);\r\n\r\n  treeSetObject2.add(11);\r\n\r\n  treeSetObject2.add(1);\r\n\r\n  treeSetObject2.add(8);\r\n\r\n  treeSetObject2.add(7);\r\n\r\n  treeSetObject1.addAll(treeSetObject2);\r\n\r\n  System.out.println(\"Values in TreeSet object 1: \" +treeSetObject1);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in TreeSet object 1: [1, 2, 3, 5, 7, 8, 9, 11]<\/pre>\n<p><span style=\"color: #008000;\"><strong>3. Object ceiling(Object o):<\/strong><\/span><\/p>\n<p>This method retrieves the least element which is greater than or equal to the given element in the argument list, or null if there is no such element in the set as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\nSystem.out.println(\"Ceiling value of '5' is:\" +treeSetObject1.ceiling(5));\r\n\r\nSystem.out.println(\"Ceiling value of '2' is:\" +treeSetObject1.ceiling(2));\r\n\r\n }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Ceiling value of '5' is:5\r\n\r\nCeiling value of '2' is:3<\/pre>\n<p><span style=\"color: #008000;\"><strong>4. void clear():<\/strong><\/span><\/p>\n<p>This method removes all of the elements from this object, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Values in TreeSet object 1:\" +treeSetObject1);\r\n\r\n  treeSetObject1.clear();\r\n\r\n  System.out.println(\"Values in TreeSet object 1:\" +treeSetObject1);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in TreeSet object 1:[1, 2, 3, 5]\r\n\r\nValues in TreeSet object 1:[]<\/pre>\n<p><span style=\"color: #008000;\"><strong>5. Object clone():<\/strong><\/span><\/p>\n<p>This method returns a copy of set, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject2 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject2=(TreeSet&lt;Integer&gt;) treeSetObject1.clone();\r\n\r\n  System.out.println(\"Values in Cloned TreeSet:\" +treeSetObject2);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in Cloned TreeSet:[1, 2, 3, 5]<\/pre>\n<p><span style=\"color: #008000;\"><strong>6. Comparator comparator():<\/strong><\/span><\/p>\n<p>This method returns the object of Comparator Class which is used to order the elements, or it returns null if it is using natural ordering as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetComparator = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetComparator= (TreeSet&lt;Integer&gt;) treeSetObject1.comparator();\r\n\r\n  System.out.println(\"Value in Tree Set Comparator: \" +treeSetComparator);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Value in Tree Set Comparator: null<\/pre>\n<p><span style=\"color: #008000;\"><strong>7. boolean contains(Object o):<\/strong><\/span><\/p>\n<p>This method returns true if specified element is present in the given set, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Checking if Tree Set Object contains element '0' : \"\r\n\r\n+treeSetObject1.contains(0));\r\n\r\n  System.out.println(\"Checking if Tree Set Object contains element '1' : \"\r\n\r\n+treeSetObject1.contains(1));\r\n\r\n  }\r\n\r\n}\r\n<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Checking if Tree Set Object contains element '0' : false\r\n\r\nChecking if Tree Set Object contains element '1' : true<\/pre>\n<p><span style=\"color: #008000;\"><strong>8. Iterator descendingIterator():<\/strong><\/span><\/p>\n<p>This method retrieves an object of Iterator class which is set in decreasing order of the elements in the Set, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  Iterator iteratorobj;\r\n\r\n  iteratorobj = treeSetObject1.descendingIterator();\r\n\r\n  while (iteratorobj.hasNext())\r\n  {\r\n\r\n    System.out.println(iteratorobj.next() + \" \");\r\n\r\n  }\r\n\r\n }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>5\r\n\r\n3\r\n\r\n2\r\n\r\n1<\/pre>\n<p><span style=\"color: #008000;\"><strong>9. NavigableSet descendingSet():<\/strong><\/span><\/p>\n<p>This method returns a all the elements in Decreasing order, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject2 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject2= (TreeSet&lt;Integer&gt;) treeSetObject1.descendingSet();\r\n\r\n  System.out.println(\"Values in Reverse order: \" +treeSetObject2);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in Reverse order: [5, 3, 2, 1]<\/pre>\n<p><span style=\"color: #008000;\"><strong>10. Object first():<\/strong><\/span><\/p>\n<p>This method returns the lowest element in the Set, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Lowest element in the tree set is : \" +treeSetObject1.first());\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Lowest element in the tree set is : 1<\/pre>\n<p><span style=\"color: #008000;\"><strong>11. Object floor(Object o):<\/strong><\/span><\/p>\n<p>This method returns the greatest element which is less than or equal to the given element in the argument list, or null if there is no such element as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Floor value of '4' : \" +treeSetObject1.floor(4));\r\n\r\n  System.out.println(\"Floor value of '5' : \" +treeSetObject1.floor(5));\r\n\r\n  }\r\n\r\n}\r\n<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Floor value of '4' : 3\r\n\r\nFloor value of '5' : 5<\/pre>\n<p><span style=\"color: #008000;\"><strong>12. SortedSet \u00a0headSet(Object toElement):<\/strong><\/span><\/p>\n<p>This method returns group of elements that are strictly less than toElement as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject2 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject2=(TreeSet&lt;Integer&gt;) treeSetObject1.headSet(4);\r\n\r\n  System.out.println(\"Values in Tress Set Head Set : \" + treeSetObject2 );\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in Tress Set Head Set : [1, 2, 3]<\/pre>\n<p><strong><span style=\"color: #008000;\">13. NavigableSet headSet(Object toElement, boolean inclusive):<\/span><\/strong><\/p>\n<p>This method Returns group of elements that are less than (or equal to, if inclusive is true) toElement as mentioned in the argument list, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject2 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject3 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject2=(TreeSet&lt;Integer&gt;) treeSetObject1.headSet(4, true);\r\n\r\n  treeSetObject3=(TreeSet&lt;Integer&gt;) treeSetObject1.headSet(4, false);\r\n\r\n  System.out.println(\"Values in Tress Set Head Set in object 2: \" + treeSetObject2 );\r\n\r\n  System.out.println(\"Values in Tress Set Head Set in object 3: \" + treeSetObject3 );\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in Tress Set Head Set in object 2: [1, 2, 3, 4]\r\n\r\nValues in Tress Set Head Set in object 3: [1, 2, 3]<\/pre>\n<p><span style=\"color: #008000;\"><strong>14. Object higher(Object o):<\/strong><\/span><\/p>\n<p>This method returns the least element in the TreeSet which is strictly greater than the given element in the argument of this method, or it will return null if there is no such element as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"highest value than 4 :\u00a0 \" + treeSetObject1.higher(4) );\r\n\r\n  System.out.println(\"highest value than 5 :\u00a0 \" + treeSetObject1.higher(5) );\r\n\r\n  }\r\n\r\n}\r\n<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>highest value than 4 :\u00a0 5\r\n\r\nhighest value than 5 :\u00a0 null<\/pre>\n<p><span style=\"color: #008000;\"><strong>15. boolean isEmpty():<\/strong><\/span><\/p>\n<p>This method returns true if the set is empty or false if set contains any element, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Is Tree Set empty ? \" +treeSetObject1.isEmpty());\r\n\r\ntreeSetObject1.clear();\r\n\r\n  System.out.println(\"Is Tree Set empty ? \" +treeSetObject1.isEmpty());\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Is Tree Set empty ? false\r\n\r\nIs Tree Set empty ? true<\/pre>\n<p><span style=\"color: #008000;\"><strong>16. Iterator iterator():<\/strong><\/span><\/p>\n<p>This method gives an object of Iterator class by which we can retrieve list in increasing order as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  Iterator iteratorobj;\r\n\r\n  iteratorobj = treeSetObject1.iterator();\r\n\r\n  while (iteratorobj.hasNext())\r\n  {\r\n\r\n    System.out.println(iteratorobj.next() + \" \");\r\n\r\n  }\r\n\r\n }\r\n\r\n}<\/pre>\n<p><strong><span style=\"color: #008000;\">Output:<\/span><\/strong><\/p>\n<pre>1\r\n\r\n2\r\n\r\n3\r\n\r\n4\r\n\r\n5<\/pre>\n<p><span style=\"color: #008000;\"><strong>17. Object last():<\/strong><\/span><\/p>\n<p>This method returns the highest element present in the treeset, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Last elememt in Tree Set object is: \"+treeSetObject1.last());\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Last elememt in Tree Set object is: 5<\/pre>\n<p><span style=\"color: #008000;\"><strong>18. Object lower(Object o):<\/strong><\/span><\/p>\n<p>This method returns the greatest element in this treeset which is strictly less than the given element in the set, or it will return null if there is no such element as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Greatest Element Less than 5: \"+treeSetObject1.lower(5));\r\n\r\n  System.out.println(\"Greatest Element Less than 1: \"+treeSetObject1.lower(1));\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Greatest Element Less than 5: 4\r\n\r\nGreatest Element Less than 1: null<\/pre>\n<p><span style=\"color: #008000;\"><strong>19. Object pollFirst():<\/strong><\/span><\/p>\n<p>This method returns as well as removes the lowest element, or it will returns null if this tree set is empty as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Removed Element using Pollfirst method \"+treeSetObject1.pollFirst());\r\n\r\n  System.out.println(\"Values in Tree Set object: \" + treeSetObject1);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Removed Element using Pollfirst method 1\r\n\r\nValues in Tree Set object: [2, 3, 4, 5]<\/pre>\n<p><span style=\"color: #008000;\"><strong>20. Object pollLast():<\/strong><\/span><\/p>\n<p>This method retrieves as well as removes the highest element, or it will returns null if this set is empty as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Removed Element using PollLast method \"+treeSetObject1.pollLast());\r\n\r\n  System.out.println(\"Values in Tree Set object: \" + treeSetObject1);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Removed Element using PollLast method 5\r\n\r\nValues in Tree Set object: [1, 2, 3, 4]<\/pre>\n<p><span style=\"color: #008000;\"><strong>21. boolean remove(Object o):<\/strong><\/span><\/p>\n<p>This method removes the element specified from the treeset, if it is present, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Is element '1' removed ? \" +treeSetObject1.remove(1));\r\n\r\n  System.out.println(\"Values in Tree Set Object: \" +treeSetObject1);\r\n\r\n  System.out.println(\"Is element '6' removed ? \" +treeSetObject1.remove(6));\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Is element '1' removed ? true\r\n\r\nValues in Tree Set Object: [2, 3, 4, 5]\r\n\r\nIs element '6' removed ? false<\/pre>\n<p><span style=\"color: #008000;\"><strong>22. Integer size():<\/strong><\/span><\/p>\n<p>This method gives the size of treeset, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  System.out.println(\"Size of the Tree Set Object : \" +treeSetObject1.size());\r\n\r\n  }\r\n\r\n}\r\n<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Size of the Tree Set Object : 5<\/pre>\n<p><span style=\"color: #008000;\"><strong>23. NavigableSet subSet(Object fromElement, boolean fromInclusive, Object toElement, boolean toInclusive):<\/strong><\/span><\/p>\n<p>This method returns group of elements that range from fromElement to toElement, Boolean keywords are added that tells whether \u201cfromElement\u201d or \u201ctoElement\u201d should be added in group or not, as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject2 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject3 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject4 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject5 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject1.add(8);\r\n\r\n  treeSetObject1.add(9);\r\n\r\n  treeSetObject1.add(10);\r\n\r\n  treeSetObject1.add(9);\r\n\r\n  treeSetObject1.add(12);\r\n\r\n  treeSetObject2=(TreeSet&lt;Integer&gt;) treeSetObject1.subSet(5, true, 10, true);\r\n\r\n  treeSetObject3=(TreeSet&lt;Integer&gt;) treeSetObject1.subSet(5, false, 10, false);\r\n\r\n  treeSetObject4=(TreeSet&lt;Integer&gt;) treeSetObject1.subSet(5, true, 10, false);\r\n\r\n  treeSetObject5=(TreeSet&lt;Integer&gt;) treeSetObject1.subSet(5, false, 10, true);\r\n\r\n  System.out.println(\"Values in tree Set Object 2 :\" +treeSetObject2);\r\n\r\n  System.out.println(\"Values in tree Set Object 3 :\" +treeSetObject3);\r\n\r\n  System.out.println(\"Values in tree Set Object 4 :\" +treeSetObject4);\r\n\r\n  System.out.println(\"Values in tree Set Object 5 :\" +treeSetObject5);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in tree Set Object 2 :[5, 8, 9, 10]\r\n\r\nValues in tree Set Object 3 :[8, 9]\r\n\r\nValues in tree Set Object 4 :[5, 8, 9]\r\n\r\nValues in tree Set Object 5 :[8, 9, 10]<\/pre>\n<p><span style=\"color: #008000;\"><strong>24. SortedSet subSet(Object fromElement, Object toElement):<\/strong><\/span><\/p>\n<p>This method gives group of elements that range from fromElement, inclusive, to toElement, exclusive. As shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject2 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject1.add(8);\r\n\r\n  treeSetObject1.add(9);\r\n\r\n  treeSetObject1.add(10);\r\n\r\n  treeSetObject1.add(9);\r\n\r\n  treeSetObject1.add(12);\r\n\r\n  treeSetObject2=(TreeSet&lt;Integer&gt;) treeSetObject1.subSet(4, 10);\r\n\r\n  System.out.println(\"Values in tree Set Object 2 :\" +treeSetObject2);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in tree Set Object 2 :[4, 5, 8, 9]<\/pre>\n<p><span style=\"color: #008000;\"><strong>25. SortedSet tailSet(Object fromElement):<\/strong><\/span><\/p>\n<p>This method returns group of elements that are greater than or equal to fromElement as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject2 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject1.add(8);\r\n\r\n  treeSetObject1.add(9);\r\n\r\n  treeSetObject1.add(10);\r\n\r\n  treeSetObject1.add(9);\r\n\r\n  treeSetObject1.add(12);\r\n\r\n  treeSetObject2=(TreeSet&lt;Integer&gt;) treeSetObject1.tailSet(8);\r\n\r\n  System.out.println(\"Values in tree Set Object 2 :\" +treeSetObject2);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in tree Set Object 2 :[8, 9, 10, 12]<\/pre>\n<p><span style=\"color: #008000;\"><strong>26. NavigableSet tailSet(Object fromElement, Boolean inclusive):<\/strong><\/span><\/p>\n<p>This method gives group of elements that are greater than (or equal to, if inclusive is true) fromElement as shown in the following program:<\/p>\n<pre>import java.util.*;\r\n\r\npublic class TreSetMethodsDemo\r\n{\r\n\r\n  public static void main(String args[]){\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject1 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject2 = new TreeSet&lt;Integer&gt;();\r\n\r\n  TreeSet &lt;Integer&gt;treeSetObject3 = new TreeSet&lt;Integer&gt;();\r\n\r\n  treeSetObject1.add(3);\r\n\r\n  treeSetObject1.add(5);\r\n\r\n  treeSetObject1.add(4);\r\n\r\n  treeSetObject1.add(1);\r\n\r\n  treeSetObject1.add(2);\r\n\r\n  treeSetObject1.add(8);\r\n\r\n  treeSetObject1.add(9);\r\n\r\n  treeSetObject1.add(10);\r\n\r\n  treeSetObject1.add(9);\r\n\r\n  treeSetObject1.add(12);\r\n\r\n  treeSetObject2=(TreeSet&lt;Integer&gt;) treeSetObject1.tailSet(8,true);\r\n\r\n  treeSetObject3=(TreeSet&lt;Integer&gt;) treeSetObject1.tailSet(8,false);\r\n\r\n  System.out.println(\"Values in tree Set Object 2 :\" +treeSetObject2);\r\n\r\n  System.out.println(\"Values in tree Set Object 3 :\" +treeSetObject3);\r\n\r\n  }\r\n\r\n}<\/pre>\n<p><span style=\"color: #008000;\"><strong>Output:<\/strong><\/span><\/p>\n<pre>Values in tree Set Object 2 :[8, 9, 10, 12]\r\n\r\nValues in tree Set Object 3 :[9, 10, 12]<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>TreeSet is a type of Collection, that implements Set Interface. In TreeSet all the values are stored in there natural order, like all integer values are stored in ascending order and strings are stored according to Dictionary values.\u00a0Apart from adding this functionality of maintaining natural ordering, TreeSet do not allow null values. 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