To get the element ordered first i.e. the first element in TreeSet, use the first() method.Create a TreeSet and add elements to it −TreeSet set = new TreeSet(); set.add("65"); set.add("45"); set.add("19"); set.add("27"); set.add("89"); set.add("57");Now, get the first element −set.first()The following is an example to get the element ordered first in TreeSet −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { TreeSet set = new TreeSet(); set.add("65"); set.add("45"); set.add("19"); ... Read More

First, create a TreeSet and add elements to it −TreeSet set = new TreeSet(); set.add("65"); set.add("45"); set.add("19"); set.add("27"); set.add("89"); set.add("57");Now, sort it in ascending order, which is the default −Iterator i = set.iterator(); while(i.hasNext()){ System.out.println(i.next()); }If you want to sort in descending order, then use the descendingIterator() method −Iterator j = set.descendingIterator(); while(j.hasNext()) { System.out.println(j.next()); }The following is an example to sort items in a TreeSet in ascending and descending order −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]){ TreeSet set ... Read More

A particular element can be searched in a LinkedList using the method java.util.LinkedList.indexOf(). This method returns the index of the first occurance of the element that is searched. If the element is not available in the LinkedList, then this method returns -1.A program that demonstrates this is given as follows −Example Live Demoimport java.util.LinkedList; public class Demo { public static void main(String[] args) { LinkedList l = new LinkedList(); l.add("A"); l.add("B"); l.add("C"); ... Read More

Use the clear() method to remove all elements from TreeSet.First, create a TreeSet and add elements −TreeSet set = new TreeSet(); set.add("65"); set.add("45"); set.add("19"); set.add("27"); set.add("89"); set.add("57");Now, remove all the elements −set.clear();The following is an example to remove all elements from TreeSet −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]){ TreeSet set = new TreeSet(); set.add("65"); set.add("45"); set.add("19"); set.add("27"); ... Read More

Use the remove() method to remove specified elements from TreeSet.At first, create a TreeSet and add elements −TreeSet set = new TreeSet(); set.add("34"); set.add("12"); set.add("67"); set.add("54"); set.add("76"); set.add("49");Now, remove the specified element i.e. 34 here −set.remove("34")The following is an example to remove specified element from TreeSet −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]){ TreeSet set = new TreeSet(); set.add("34"); set.add("12"); set.add("67"); set.add("54"); ... Read More

Use the clear() method to remove all values from TreeMap.Let us first create a TreeMap −TreeMap m = new TreeMap();Add some elements to the TreeMap −m.put(1, "PHP"); m.put(2, "jQuery"); m.put(3, "JavaScript"); m.put(4, "Ruby"); m.put(5, "Java"); m.put(6, "AngularJS"); m.put(7, "ExpressJS");Let us now remove all the values −m.clear();The following is an example to remove all values from TreeMap −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]) { TreeMap m = new TreeMap(); m.put(1, "PHP"); m.put(2, "jQuery"); ... Read More

To get Sub Map in Java, use the submap() method. It returns the elements in a range from the Map.First, create a TreeMap and add elements −TreeMap m = new TreeMap(); m.put(1, "PHP"); m.put(2, "jQuery"); m.put(3, "JavaScript"); m.put(4, "Ruby"); m.put(5, "Java"); m.put(6, "AngularJS"); m.put(7, "ExpressJS");Now, get the Sub Map between 4 and 6 −m.subMap(4, 6)The following is an example to get Sub Map from Tree Map in JavaExample Live Demoimport java.util.*; public class Demo { public static void main(String args[]){ TreeMap m = new TreeMap(); m.put(1, ... Read More

An element in an ArrayList can be searched using the method java.util.ArrayList.indexOf(). This method returns the index of the first occurance of the element that is specified. If the element is not available in the ArrayList, then this method returns -1.A program that demonstrates this is given as follows −Example Live Demoimport java.util.ArrayList; import java.util.List; public class Demo { public static void main(String[] args) { List aList = new ArrayList(); aList.add("A"); aList.add("B"); aList.add("C"); ... Read More

The java.util.ArrayList.contains() method can be used to check if a Java ArrayList contains a given item or not. This method has a single parameter i.e. the item whose presence in the ArrayList is tested. Also it returns true if the item is present in the ArrayList and false if the item is not present.A program that demonstrates this is given as follows −Example Live Demoimport java.util.ArrayList; import java.util.List; public class Demo { public static void main(String[] args) { List aList = new ArrayList(); aList.add("A"); ... Read More

TreeSet is a class in Java that implements the Set interface. It stores unique values in a sorted order. It is similar to HashSet, but the difference is that TreeSet stores elements in a sorted manner, while HashSet does not guarantee any order. Our task is to check if a particular value exists in a TreeSet in Java. We can do this using the following methods: Using contains() Method Using Streams API Using contains() Method The contains() method of the TreeSet class is used for checking if a particular value ... Read More