Many a times random number generation is required in coding, especially in testing. When different sequence of numbers are passed multiple times, a correct result should to be obtained; testing requires this. Sometimes, the same sequence of random numbers is also required multiple times in testing; when the same sequence is passed number of times, …
Two classes exist in java.util package to get informed whenever an object changes its properties. The class which you would like to observe (like a Student object) should extend Observable and the class which would like to keep a vigilance (like Principal) should extend Observer. One program using both the classes with explanation is given …
Date and Time manipulation is a must in every programming. Date, GregorianCalendar, SimpleDateFormat classes placed in java.util package comes to the rescue for all possible operations on date and time. Following postings of this same Web site give all the possible operations on Date and Time manipulations. 1. class Date 2. class GregorianCalendar 3. SimpleDateFormat …
SimpleDateFormat class is used for many jobs of getting time as per the locale, converting date one form to the other etc. Date formats like yyyy-mm-dd are also shown with examples. 1. SimpleDateFormat to set time as per the country with Locale 2. SimpleDateFormat to convert Date object to String form 3. SimpleDateFormat to convert …
What is Java deprecation and why it is necessary in a programming language, say, Java? Java Deprecation: 1. A method introduced in one version of Java may become outdated in the next version as next version method is a better method than the old version method. We call old version method is obsolete. The obsolete …
In Java coding, many times it is required to read the system time and at the same time convert the system time into objects of Date and Calendar etc. Following code illustrates. Example on Convert Milliseconds to Date Java import java.util.*; public class Demo { public static void main(String args[]) { // to read current …
It is many times required in coding to compare two dates like one is before the other or after or equals (like dates of joining a job). To manipulate dates, Java comes with mainly two classes from java.util package Date and Calendar (its subclass GregorianCalendar). Three programs are given to compare dates with classes Date, …
For comparing two characters logical equals (==) operator can be used. Alternatively, the chars can be passed to Character constructor and compared with equals() method. The following program illustrates. Program on Char Comparison Java public class CharComparison { public static void main(String args[]) { char ch1 = ‘A’; char ch2 = ‘A’; char ch3 = …
class Date Methods Summary: By the end of this tutorial "class Date Methods", you will come to know how to use Java Date class methods. Introduction to class Date Methods java.util.Date class constructor is used to print the system date. It comes with many methods to manipulate the date. But these methods are deprecated in …
What is Deprecation Meaning? "Deprecation", warning raised, by the Java compiler, is very common to a Java programmer. It is raised when the programmer uses a method that is found faulty or problematic. A substitute method will be available in the later versions. For example, readLine() method of DataInputStream was deprecated in JDK 1.1 and …
class Random Generate random numbers Summary: By the time you complete this "class Random Generate random numbers", you will understand of how to generate random numbers in Java. Introduction to class Random Generate random numbers Generating different numbers at different times of execution, by the same program, is known as random number generation. Random numbers …
Observer Observable Introduction Sometimes, it may be necessary to get notified when the data changes in a data structure. To accomplish this job, the Java designers introduced Observer and Observable classes with JDK 1.0, the starting version itself. Observer is an interface and Observable is a class, both from java.util package. As the names are …
class Calendar TimeZone Locale Summary: After reading this "class Calendar TimeZone Locale" you will come to know the usage of the methods of Date and Calendar class. Also learn to print the date as per timezone or country. Introduction Date and Calendar We know many methods of Date class are deprecated; observe the screenshot of …
After knowing the data structures from java.util package, let us discuss about the remaining classes of java.util package. The classes include Date and GregorianCalendar to manipulate dates, Random class to generate random numbers and StringTokenizer to separate the string into individual words (known as tokens). The other classes less used are Observer, Observable, Timer and …
GregorianCalendar is a concrete class, a subclass of abstract class Calendar. The GregorianCalendar class represents the calendar we use everyday. It is used to manipulate date and retrieve date particulars. This was introduced with JDK 1.1. Following statement gives the class signature public class GregorianCalendar extends Calendar Following program illustrates the usage of a few …
Timer TimerTask Java Introduction The classes, Timer and TimerTask from java.util package, introduced with JDK 1.3, are used with threads to animate the images at regular intervals of time. If the stipulated (delay) period of time is over, the Timer object can generate events. Simply by handling the event, the programmer can execute some user-defined …
