Programming Articles - Page 2915 of 3363

In order to generate Random long type numbers in Java, we use the nextLong() method of the java.util.Random class. This returns the next random long value from the random generator sequence.Declaration − The java.util.Random.nextLong() method is declared as follows −public long nextLong()Let us see a program to generate random long type numbers in Java −Example Live Demoimport java.util.Random; public class Example {    public static void main(String[] args) {       Random rd = new Random(); // creating Random object       System.out.println(rd.nextLong()); // displaying a random long value    } }Output-4787108556148621714Note - The output may vary on Online compilers.Read More

The package for a class can be obtained using the java.lang.Class.getPackage() method with the help of the class loader of the class. If there is no package object created by the class loader of the class, then null is returned.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Date; public class Main {    public static void main(String[] args) {       Date d = new Date();       Package p = d.getClass().getPackage();       String pName = p.getName();       System.out.println("The package name is: " + pName);    } }OutputThe package name is: ... Read More

A list of all the public methods of a class or interface that is represented by an object are provided using the method java.lang.Class.getMethods(). The public methods include that are declared by the class or interface and also those that are inherited by the class or interface.Also, the getMethods() method returns a zero length array if the class or interface has no public methods or if a primitive type, array class or void is represented in the Class object.A program that demonstrates this is given as follows −Example Live Demoimport java.lang.reflect.Method; public class Main {    public static void main(String[] argv) ... Read More

The list of all the declared methods can be obtained using the java.lang.Class.getDeclaredMethods() method. This method returns an array that contains all the Method objects with public, private, protected and default access. However, the inherited methods are not included.Also, the getDeclaredMethods() method returns a zero-length array if the class or interface has no methods or if a primitive type, array class or void is represented in the Class object.A program that demonstrates this is given as follows −Example Live Demoimport java.lang.reflect.Method; public class Main {    public static void main(String[] argv) throws Exception {       Class c = java.lang.String.class; ... Read More

In this article, we will fill elements in a char array using Java. We will be using the Arrays.fill() method to fill it with a specific character. This method allows us to assign a single character value to all elements in the array. We will fill the array with the character 'A' and then print the array using Arrays.toString() to display its contents in a readable format. Problem Statement Write a Java program to fill elements in a char array − Input charValue = 'A' Output The char array content is: [A, A, A, A, A] Steps to fill elements in a ... Read More

Two double arrays can be compared in Java using the java.util.Arrays.equals() method. This method returns true if the arrays are equal and false otherwise. The two arrays are equal if they contain the same number of elements in the same order.A program that compares two double arrays using the Arrays.equals() method is given as follows −Example Live Demoimport java.util.Arrays; public class Demo {    public static void main(String[] argv) throws Exception {       boolean flag = Arrays.equals(new double[] { 7.5D, 9.2D, 1.8D }, new double[] { 7.5D, 9.2D, 1.8D });       System.out.println("The two double arrays are equal? ... Read More

In order to swap elements of ArrayList with Java collections, we need to use the Collections.swap() method. It swaps the elements at the specified positions in the list.Declaration −The java.util.Collections.swap() method is declared as follows −public static void swap(List list, int i, int j)where i is the index of the first element to be swapped, j is the index of the other element to be swapped and list is the list where the swapping takes place.Let us see a program to swap elements of ArrayList with Java collections −Example Live Demoimport java.util.*; public class Example {    public static void ... Read More

In order to shuffle elements of ArrayList with Java Collections, we use the Collections.shuffle() method. The java.util.Collections.shuffle() method randomly permutes the list using a default source of randomness.Declaration −The java.util.Collections.shuffle() method is declared as follows −public static void shuffle(List list)Let us see a program to shuffle elements of ArrayList with Java Collections −Example Live Demoimport java.util.*; public class Example {    public static void main (String[] args) {       ArrayList list = new ArrayList();       list.add(1);       list.add(2);       list.add(7);       list.add(8);       list.add(3);       list.add(9); ... Read More

In order to reverse order of all elements of ArrayList with Java Collections, we use the Collections.reverse() method.Declaration −The java.util.Collections.reverse method is declared as follows −public static void reverse(List list)Let us see a program to reverse order of all elements of ArrayList with Java Collections −Example Live Demoimport java.util.*; public class Example {    public static void main (String[] args) {       ArrayList list = new ArrayList();       list.add(1);       list.add(2);       list.add(7);       list.add(8);       list.add(3);       list.add(9);       System.out.println("Original list : " + ... Read More

In order to replace all occurrences of specified element of ArrayList with Java Collections, we use the Collections.replaceAll() method. This method returns true if list contains one or more elements e such that (oldVal==null ? e==null : oldVal.equals(e)).Declaration −The java.util.Collections.replaceAll() is declared as follows −public static boolean replaceAll(List list, T oldVal, T newVal)where oldVal is the element value in the list to be replaced, newVal is the element value with which it is replaced and list is the list in which replacement takes place.Let us see a program to replace all occurrences of specified element of ArrayList with Java ... Read More