Get the TreeMap size using the size() method.First, create a TreeMap and add elements to it −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");Count the number of elements in the above TreeMap or get the size using the size() method as shown below −m.size()To get the size of TreeMap, the following is the code −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

Use the lastKey() method to get the highest key stored in TreeMap.Let us first set the TreeMap and add some elements to it −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 highest key −m.lastKey()The following is an example to get the highest key in 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");       m.put(3, "JavaScript");       m.put(4, "Ruby"); ... Read More

The last element of a Linked List can be retrieved using the method java.util.LinkedList.getLast() respectively. This method does not require any parameters and it returns the last element of the LinkedList.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("Andy");       l.add("Sara");       l.add("James");       l.add("Betty");       l.add("Bruce");       System.out.println("The last element of the Linked List is : " + l.getLast());    } }OutputThe last ... Read More

The first element can be deleted from a LinkedList by using the method java.util.LinkedList.removeFirst(). This method does not have any parameters and it returns the first element of the LinkedList.The last element can be deleted from a LinkedList by using the method java.util.LinkedList.removeLast(). This method does not have any parameters and it returns the last element of the LinkedList.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("Apple");       l.add("Mango");       ... Read More

Elements can be added at the beginning of a LinkedList by using the method java.util.LinkedList.addFirst(). This method has a single argument i.e. the element that is to be added at the beginning of the LinkedList.Elements can be added at the end of a LinkedList by using the method java.util.LinkedList.addLast(). This method has a single argument i.e. the element that is to be added at the end of the LinkedList.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();   ... Read More

Use the firstKey() method to get the lowest key stored in TreeMap.Let us first set the TreeMap and add some elements to it −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 lowest key −m.firstKey()The following is an example to get the lowest key in 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");       m.put(3, "JavaScript");       m.put(4, "Ruby"); ... Read More

Use the headMap() method in Java to get ahead map. It returns a view of the portion of this map whose keys are less than or equal to.Let’s say you need to get the portion of the map above the set map (and not inclusive of it). For that, use the headMap() method like this −m.headMap(4)If you want the value 4 to be included as well, then set it as true −m.headMap(4, true)The following is an example to get Head Map from Java TreeMap −Example Live Demoimport java.util.*; public class Demo {    public static void main(String args[]) {     ... Read More

To check if a particular value exists in TreeMap, use the containsValue() method.Create a TreeMap first and add some 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, let’s say we need to check that value “Java” exists or not. For that, use the containsValue() method like this −m.containsValue("Java")The following is an example to check if a particular value exists in TreeMap −Example Live Demoimport java.util.*; public class Demo {    public static void main(String args[]) {       TreeMap m = new TreeMap();       m.put(1, "PHP"); ... Read More

To check if a particular key exists in TreeMap, use the containsKey() method.Create a TreeMap first and add some 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, let’s say we need to check that key 5 exists or not. For that, set the containsKey() method like this −m.containsKey(5)The following is an example to check if a particular key exists in TreeMap −Example Live Demoimport java.util.*; public class Demo {    public static void main(String args[]) {       TreeMap m = new TreeMap();       m.put(1, "PHP"); ... Read More

Let us create TreeMap in Java. It stores unique elements in ascending order −TreeMap m = new TreeMap();Now let us add some elements −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");The following is an example to create a 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");       m.put(3, "JavaScript");       m.put(4, "Ruby");       m.put(5, "Java");       m.put(6, "AngularJS");       ... Read More