Java Articles - Page 704 of 745

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

The removeRange() method of the ArrayList class removes all of the elements from this List whose index is between fromIndex and toIndex.Exampleimport java.util.*; public class ArrayListDemo extends ArrayList{    public static void main(String[] args) {       ArrayListDemo arrlist = new ArrayListDemo();       arrlist.add(10);       arrlist.add(12);       arrlist.add(31);       System.out.println("The list:" + arrlist);       arrlist.removeRange(0,2);       System.out.println("The list after using removeRange:" + arrlist);    } }OutputThe list:[10, 12, 31] The list after using removeRange:[31]

The set() method of the ArrayList class replaces the element at the specified position in this list with the specified element.Exampleimport java.util.ArrayList; public class Sample {    public static void main(String args[]) {       ArrayList al = new ArrayList();       System.out.println("Initial size of al: " + al.size());       al.add("C");       al.add("A");       al.add("E");       al.add(1, "A2");       System.out.println("Size of al after additions: " + al.size());       System.out.println("Contents of al: " + al);       System.out.println("Size of al after deletions: " + al.size());     ... Read More

The listIterator(int index) method of the java.util.LinkedList class returns a list-iterator of the elements in this list (in proper sequence), starting at the specified position in the 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); Iterator x = list.listIterator(1); while (x.hasNext()) { System.out.println(x.next()); } } } Output LinkedList:[Hello, 2, Chocolate, 10] 2 Chocolate 10

The trimToSize() method of the java.util.ArrayList class trims the capacity of this ArrayList instance to be the list's current size. An application can use this operation to minimize the storage of an ArrayList instance.Exampleimport java.util.ArrayList; public class ArrayListDemo {    public static void main(String args[]) {       ArrayList arrlist = new ArrayList(5);       arrlist.add(35);       arrlist.add(20);       arrlist.add(25);       arrlist.trimToSize();       for (Integer number : arrlist) {          System.out.println("Number = " + number);       }    } }OutputNumber = 35 Number = 20 Number = 25

Since a vector stores elements in the form of objects, you can store objects of various types (heterogeneous) in it.Example:import java.util.*; class Demo{} public class VectorSample {    public static void main(String args[]) {       Demo obj = new Demo();       Vector v = new Vector(3, 2);       System.out.println("Initial size: " + v.size());       System.out.println("Initial capacity: " + v.capacity());       v.addElement(new Integer(1));       v.addElement(new String("krishna"));       v.addElement(new Float(3.5f));       v.addElement(obj);       System.out.println("Capacity after four additions: " + v.capacity());    } }

The size of a vector represents the number of components in the vector. The capacity of a vector represents the maximum number of elements the vector can hold.Example:import java.util.*; public class VectorDemo {    public static void main(String args[]) {       Vector v = new Vector(3, 2);       System.out.println("Initial size: " + v.size());       System.out.println("Initial capacity: " + v.capacity());       v.addElement(new Integer(1));       v.addElement(new Integer(2));       v.addElement(new Integer(3));       v.addElement(new Integer(4));       System.out.println("Capacity after four additions: " + v.capacity());       v.addElement(new ... Read More

Both Vector and ArrayList implement the List interface, and each of them uses (dynamically resizable) arrays for their internal data structure, similar to using an ordinary array. However, there are many differences between ArrayList and Vector classes hence by reading this article, you will learn what ArrayList and Vector class are and their major difference that helps you to choose which one to opt for. Understanding ArrayList and Vector Class In addition to the Arrays class, Java provides an ArrayList class that can be used to create containers that stores lists of objects. ArrayList is considered to be a growable ... Read More

The ensureCapacity(int minCapacity) method of the class java.util.ArrayList increases the capacity of this ArrayList instance, if necessary, to ensure that it can hold at least the number of elements specified by the minimum capacity argument.Exampleimport java.util.ArrayList; public class ArrayListDemo {    public static void main(String args[]) {       ArrayList arrlist = new ArrayList(5);       arrlist.add(10);       arrlist.add(50);       arrlist.add(30);       arrlist.ensureCapacity(15);       for (Integer number : arrlist) {          System.out.println("Number = " + number);       }    } }OutputNumber = 10 Number = 50 Number = 30