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
Java Articles
Page 14 of 450
What are parametrized constructors in Java?
A constructor is similar to method and it is invoked at the time creating an object of the class, it is generally used to initialize the instance variables of a class. The constructors have same name as their class and, have no return type.Parameterized constructorsA parameterized constructor accepts parameters with which you can initialize the instance variables. Using parameterized constructor, you can initialize the class variables dynamically at the time of instantiating the class with distinct values.Syntaxpublic class Sample{ Int i; public sample(int i){ this.i = i; } }Examplepublic class Test { String ...
Read MoreSort an arrays of 0's, 1's and 2's using Java
Given an array of 0, 1 and 2 sort the element in an order such that all the zeros come first before 1 and all the 2’s in the end. We have to sort all the elements of the array in-place.We can solve this problem using DNF (Dutch National Flag) Sorting Algorithm. For example, Input-1 −arr[ ]= {2, 0, 0, 1, 2, 1 }Output −0 0 1 1 2 2Explanation − Sorting the given array of elements containing 0, 1 and 2 using the DNF Sorting Algorithm, it will print the output as {0, 0, 1, 1, 2, 2}.Input-2 −arr[ ...
Read MoreHow to create a default constructor in Java?
Default constructor (No-arg constructor)A no-arg constructor doesn’t accepts any parameters, it instantiates the class variables with their respective default values (i.e. null for objects, 0.0 for float and double, false for Boolean, 0 for byte, short, int and, long).There is no need to invoke constructors explicitly these are automatically invoked at the time of instantiation.Rules to be rememberedWhile defining the constructors you should keep the following points in mind.A constructor does not have return type.The name of the constructor is same as the name of the class.A constructor cannot be abstract, final, static and Synchronized.You can use the access specifiers ...
Read MoreWhat are various ways to compare time values in Java?
The LocalTime class represents the local time i.e. the time without time zone. This class provides various methods such as isBefore(), isAfter() and, isEqual() to compare two times.Exampleimport java.time.LocalTime; public class Test { public static void main(String args[]) { LocalTime Time1 = LocalTime.of(10, 15, 45); LocalTime Time2 = LocalTime.of(07, 25, 55); Boolean bool1 = Time1.isAfter(Time2); Boolean bool2 = Time1.isBefore(Time2); if(bool1){ System.out.println(Time1+" is after "+Time2); }else if(bool2){ System.out.println(Time1+" is ...
Read MoreHow to compare two dates in String format in Java?
The java.text.SimpleDateFormat class is used to format and parse a string to date and date to string.One of the constructors of this class accepts a String value representing the desired date format and creates SimpleDateFormat object. To parse/convert a string as a Date object Instantiate this class by passing desired format string.Parse the date string using the parse() method.The util.Date class represents a specific instant time This class provides various methods such as before(), after() and, equals() to compare two datesExampleOnce you create date objects from strings you can compare them using either of these methods as shown below −import java.text.ParseException; import ...
Read MoreHow to parse date sting to date in Java?
You can parse a string containing a data to date value using the following ways −The constructor SimpleDateFormat class accepts a String value representing the desired date format and creates this object. You can parse the date string using the parse() method of this class.The parse() method of the LocalDate class accepts a String value representing a date and returns a LocalDate object.The DateUtils provides utility to format date you can find it in apache.commons package. The parseDate() method of the DateUtils class accepts a format string and a date string as parameters and returns a Date object.The parse() method of ...
Read MoreHow to print date using GregorianCalendar class in Java?
The GregorianCalendar class supports standard calendars it supports Julian and Gregorian calendars you can create an object of GregorianCalendar using one of its constructors. Following are various examples demonstrating how to print date using this class −ExampleFollowing example creates GregorianCalander by passing year, month and date values as parameters to its constructor and prints the date −import java.util.Calendar; import java.util.GregorianCalendar; public class Test { public static void main(String args[]){ //Instantiating the GregorianCalendar GregorianCalendar cal = new GregorianCalendar(2018, 6, 27); System.out.println(cal); System.out.println("Date: "+cal.get(Calendar.DATE)); System.out.println("Month: "+cal.get(Calendar.MONTH)); ...
Read MoreCan we define an enum inside a class in Java?
Enumerations in Java represents a group of named constants, you can create an enumeration using the following syntaxenum Days { SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY }Yes, we can define an enumeration inside a class. You can retrieve the values in an enumeration using the values() method.Examplepublic class EnumerationExample { enum Enum { Mango, Banana, Orange, Grapes, Thursday, Apple } public static void main(String args[]) { Enum constants[] = Enum.values(); System.out.println("Value of constants: "); for(Enum d: constants) { System.out.println(d); ...
Read MoreHow to format time using printf() method in Java?
The printf() method is used to print a formatted string, it accepts a string representing a format string and an array of objects representing the elements that are to be in the resultant string, if the number of arguments are more than the number of characters in the format string the excess objects are ignored.Following table lists the various format characters to print date printf() method along with their description −Format CharactersDescription'B'The corresponding argument is formatted as full month name.'b'The corresponding argument is formatted as abbreviated month name.'h'The corresponding argument is formatted as abbreviated month name.'A'The corresponding argument is formatted as ...
Read MoreCan we define an enum inside a method in Java?
Enumerations in Java represents a group of named constants, you can create an enumeration using the following syntax −enum Days { SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY }We can an enumeration inside a class. But, we cannot define an enum inside a method. If you try to do so it generates a compile time error saying “enum types must not be local”.Examplepublic class EnumExample{ public void sample() { enum Vehicles { Activa125, Activa5G, Access125, Vespa, TVSJupiter; } } }ErrorEnumExample.java:3: error: enum types must not be local ...
Read More