Object Oriented Programming Articles - Page 875 of 915

The synchronizedList(List list) method of the Collections class accepts a List object and returns a synchronized list backed by the specified list.Example:import java.util.ArrayList; import java.util.Collections; import java.util.LinkedHashSet; import java.util.Set; public class ArrayListSample {    public static void main(String[] args){       ArrayList list = new ArrayList();       list.add("JavaFx");       list.add("Java");       list.add("WebGL");       list.add("OpenCV");       Set set = new LinkedHashSet(list);       Collections.synchronizedList(list);       System.out.println(list);    } }Output:[JavaFx, Java, WebGL, OpenCV]

The Collections class provides a method named reverse() this method accepts a list and reverses the order of elements in it.Example:import java.util.ArrayList; import java.util.Collections; import java.util.LinkedHashSet; import java.util.Set; public class Sample {    public static void main(String[] args){       ArrayList list = new ArrayList();       list.add("JavaFx");       list.add("Java");       list.add("WebGL");       list.add("OpenCV");       Set set = new LinkedHashSet(list);       System.out.println(set);       Collections.reverse(list);       System.out.println(list);    } }Output:[JavaFx, Java, WebGL, OpenCV] [OpenCV, WebGL, Java, JavaFx]

The removeLast() method of the java.util.LinkedList class removes and returns the last element of this list.Example:import java.util.*; public class LinkedListDemo {    public static void main(String[] args) {       LinkedList list = new LinkedList();       list.add("Hello");       list.add(2);       list.add("Chocolate");       list.add("10");       System.out.println("LinkedList:" + list);       System.out.println("Last element:" + list.removeLast());       System.out.println("LinkedList:" + list);    } }Output:LinkedList:[Hello, 2, Chocolate, 10] Last element:10 LinkedList:[Hello, 2, Chocolate]

The removeFirst() method of the java.util.LinkedList class removes and returns the first element from this list.Example:import java.util.*; public class LinkedListDemo {    public static void main(String[] args) {       LinkedList list = new LinkedList();       list.add("Hello");       list.add(2);       list.add("Chocolate");       list.add("10");       System.out.println("LinkedList:" + list);       System.out.println("First element:" + list.removeFirst());       System.out.println("LinkedList:" + list);    } }Output:LinkedList:[Hello, 2, Chocolate, 10] First element:Hello LinkedList:[2, Chocolate, 10]

The getLast() method of the class java.util.LinkedList returns the last element in this list.Example:import java.util.*; public class LinkedListDemo {    public static void main(String[] args) {       LinkedList list = new LinkedList();       list.add("Hello");       list.add(2);       list.add("Chocolate");       list.add("10");       System.out.println("LinkedList:" + list);       System.out.println("Last Element :" + list.getLast());    } }Output:LinkedList:[Hello, 2, Chocolate, 10] Last Element :10

The getFirst() method of the class java.util.LinkedList returns the first element of the current list. Example Live Demo import java.util.*; public class LinkedListDemo { public static void main(String[] args) { LinkedList list = new LinkedList(); list.add("Hello"); list.add(2); list.add("Chocolate"); list.add("10"); System.out.println("LinkedList:" + list); System.out.println("First Element :" + list.getFirst()); } } Output LinkedList:[Hello, 2, Chocolate, 10] First Element :Hello

The addLast(E e) method of the java.util.LinkedList class inserts the specified element at the end of this list.Example:import java.util.*; public class LinkedListDemo {    public static void main(String[] args) {       LinkedList list = new LinkedList();       list.add("Hello");       list.add(2);       list.add("Chocolate");       list.add("10");       System.out.println("LinkedList:" + list);       list.addLast("Element");       System.out.println("LinkedList:" + list);    } }Output:LinkedList:[Hello, 2, Chocolate, 10] LinkedList:[Hello, 2, Chocolate, 10, Element]

The addFirst(E e) method of the class java.util.LinkedList inserts the specified element at the beginning of this list.Example:public class LinkedListDemo {    public static void main(String[] args) {       LinkedList list = new LinkedList();       list.add("Hello");       list.add(2);       list.add("Chocolate");       list.add("10");       System.out.println("LinkedList:" + list);       list.addFirst("Element");       System.out.println("LinkedList:" + list);    } }Output:LinkedList:[Hello, 2, Chocolate, 10] LinkedList:[Element, Hello, 2, Chocolate, 10]

The add(int index, E element) method of the java.util.ArrayList class inserts the specified element E at the specified position in this list. It shifts the element currently at that position (if any) and any subsequent elements to the right (will add one to their indices).Exampleimport java.util.ArrayList; public class ArrayListDemo {    public static void main(String[] args) {       ArrayList arrlist = new ArrayList(5);       arrlist.add(15);       arrlist.add(22);       arrlist.add(30);       arrlist.add(40);       arrlist.add(2,25);       for (Integer number : arrlist) {          System.out.println("Number = " + number);       }    } }OutputNumber = 15 Number = 22 Number = 25 Number = 30 Number = 40

The add(E e) method of the java.util.ArrayList class appends the specified element E to the end of the list.Example:import java.util.ArrayList; public class ArrayListDemo {    public static void main(String[] args) {       ArrayList arrlist = new ArrayList(5);       arrlist.add(15);       arrlist.add(20);       arrlist.add(25);       for (Integer number : arrlist) {          System.out.println("Number = " + number);       }    } }Output:Number = 15 Number = 20 Number = 25