Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Articles by Chandu yadav
Page 33 of 81
Replace All Elements Of ArrayList with with Java Collections
In order to replace all elements of ArrayList with Java Collections, we use the Collections.fill() method. The static void fill(List list, Object element) method replaces all elements in the list with the specified element in the argument.Declaration −The java.util.Collections.fill() method is declared as follows −public static void fill(List
Read MoreSwap elements of ArrayList with Java collections
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 −Exampleimport java.util.*; public class Example { public static void main ...
Read MoreHow to prevent Reflection to break a Singleton Class Pattern?
A Singleton pattern states that a class can have a single instance and multiple instances are not permitted to be created. For this purpose, we make the constructor of the class a private and return a instance via a static method. But using reflection, we can still create multiple instance of a class by modifying the constructor scope. See the example below −Example - Breaking Singletonimport java.io.Serializable; import java.lang.reflect.Constructor; import java.lang.reflect.InvocationTargetException; public class Tester { public static void main(String[] args) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException{ A a = A.getInstance(); ...
Read MoreDisplay the package name of a class in Java
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 −Exampleimport 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: java.utilNow ...
Read MoreImplement Runnable vs Extend Thread in Java
We can create Thread by either by implementing a runnable interface or by extending Thread class. Below are the detailed steps of using both ways to create Thread.Create a Thread by Implementing a Runnable InterfaceIf your class is intended to be executed as a thread then you can achieve this by implementing a Runnable interface. You will need to follow three basic steps −Step 1As a first step, you need to implement a run() method provided by a Runnable interface. This method provides an entry point for the thread and you will put your complete business logic inside this method. ...
Read Moreinstanceof operator vs isInstance method in java
isInstance method is equivalent to instanceof operator. The method is used in case of objects are created at runtime using reflection. General practice says if type is to be checked at runtime then use isInstance method otherwise instanceof operator can be used. See the example below −Examplepublic class Tester{ public static void main(String[] args) throws ClassNotFoundException { Integer i = new Integer(10); System.out.println(usingInstanceOf(i)); System.out.println(usingIsInstance(i)); } public static String usingInstanceOf(Object i){ if(i instanceof String){ return "String"; } ...
Read MoreJagged Array in Java
Jagged array is a multidimensional array where member arrays are of different size. For example, we can create a 2D array where first array is of 3 elements, and is of 4 elements. Following is the example demonstrating the concept of jagged array.Examplepublic class Tester { public static void main(String[] args){ int[][] twoDimenArray = new int[2][]; //first row has 3 columns twoDimenArray[0] = new int[3]; //second row has 4 columns twoDimenArray[1] = new int[4]; int counter = 0; ...
Read MoreUse reflection to create, fill, and display an array in Java
An array is created using the java.lang.reflect.Array.newInstance() method. This method basically creates a new array with the required component type as well as length.The array is filled using the java.lang.reflect.Array.setInt() method. This method sets the required integer value at the index specified for the array.The array displayed using the for loop. A program that demonstrates this is given as follows −Exampleimport java.lang.reflect.Array; public class Demo { public static void main (String args[]) { int arr[] = (int[])Array.newInstance(int.class, 10); int size = Array.getLength(arr); for (int i = 0; i
Read MoreWhen should you use a class vs a struct in C++?
Structures and classes are very similar in C++ except for some differences. So details about these differences are given below that help to decide when to use a class or structure in C++.Differences between Class and StructureAll the members of a class are private by default. This is different compared to structures as all the members of a structure are public by default.A program that demonstrates a class in C++ is given as follows −Example#include using namespace std; class Example { int val; }; int main() { Example obj; obj.val = 20; return 0; }This ...
Read MorePython Text Sequence Types
In python the str object, handles the text or string type data. Strings are immutable. The strings are sequence of Unicode characters. We can use single quote, double quotes or triple quotes to define the string literals. ‘This is a string with single quote’ “Another Text with double quotes” ‘’’Text using three single quotes’’’ or “””Text using three double quotes””” We can use triple quotes to assign multiline strings in python. There is different string related functions. Some of the String methods are as follows − Sr.No. Operation/Functions & Description 1 s.capitalize() Convert first ...
Read More