Java Character class comes with many static methods with which a given character can be tested for a criteria like it is upper case letter or lower case letter or a digit etc. It is placed by Designers in java.lang package so that is it is implicitly imported and available fro each program you write. …
Character is a wrapper class representing data type char. This class includes many static methods with which a character can be tested for a specific requirement like validations etc. Character class discussion is available at class Character
Vector is the mostly used data structure. Vector methods are synchronized implicitly and best suitable for usage in multithreaded environment. Total five programs are given on Vector: 1. Vector Methods 2. Vector Generics 3. Vector Retrieval 4. Vector Play With 5. Vector vs ArrayList
Vector class Java is the general purpose Data Structure used very often by the Programmers. Vector, though belongs to legacy classes (DS of JDK 1.0), it can use the methods of List interface as Vector implements List from JDK 1.2. In this way, Vector became part of collections framework. All Java Vector class methods are …
To manipulate the elements of an array, Java designers introduced java.util.Arrays class. The Arrays class comes with many static methods with which array elements manipulation becomes easy, else, a lot of code is needed by the programmer. A. For Arrays methods 1. class Arrays API Methods B. For Methods Usage 1. Printing array elements with …
There may be a necessity to convert integer array to int array. For example, a DS stores only integer objects and it may be required to read the integer values into an int array. That is, Integer Array to int Array. Following is the example on Integer Array to int Array. public class IntegerTointArray { …
Java supports graphics. Drawing different geometrical figures is known as graphics. Java comes with java.awt.Graphics many methods of drawing. Following programs use Frame or Applet window to draw figures. A. Basic Programs 1. Graphics – Introduction B. For the usage of methods of Graphics class 1. For darwLine(): Drawing Lines 2. For drawString(): Drawing Strings …
java.awt.Graphics comes with many methods of drawing different geometrical figures. The Graphics object is passed as parameter to paint() method. Following programs use Frame or Applet window to draw figures. A. Basic Programs 1. Graphics – Introduction B. For the usage of methods of Graphics class 1. For darwLine(): Drawing Lines 2. For drawString(): Drawing …
How to get the current date Java? Many ways are discussed in the next programs. System class also contains the static method currentTimeMillis() to support system time. Te constructor of Date class form java.util package can be used to get the system date or current date. The Date class methods are deprecated and means not …
Sometimes in Java, it is necessary to convert in between Date to Calendar and Calendar to Date classes. Note: It is assumed that you know about the basic concepts of class Date and class GregorianCalendar. It is done in the following code. import java.util.*; public class DateToCalendar { public static void main(String args[]) { Date …
To manipulate dates, Java comes with three classes – Date, Calendar and GregorianCalendar, all from java.util package. Many of Date class methods are deprecated in favor Calendar. But Calendar class is abstract class and more features and methods are given in its subclass GregorianCalendar. Class signature of Calendar class as defined in java.util package. public …
Date Java used in routine coding to store dates in a DS at runtime or writing to a database like employees joining dates or birth dates or to manipulate dates. To do the job, Date class comes with many methods and fields. Many methods of Date class are deprecated. Designers advice to discontinue using Date …
Two Simple Examples given to convert from Calendar to java.sql.Date and Date to java.sql.Date in this tutorial Date Calendar Conversions. Following program on Date Calendar Conversions converts from Calendar to java.sql.Date and Date to java.sql.Date. public class Demo { public static void main(String args[]) { java.util.Calendar cal = java.util.Calendar.getInstance(); // takes current system time System.out.println(“Current …
Just like with primitive data types, arrays, in Java, can be created with objects. Infact, objects are reference types. In the following program, Student objects arrays are created in different styles and their values are printed. Example on Objects Array public class Student { int marks; public static void main(String args[]) { Student std1[] = …
The super class of all classes of Java is Object class. If you do not extend any class to your class, implicitly JRE (Java Runtime Environment) extends Object class. See the following simple class. Let us see more on Java Object class. Java Object class: You write like this: public class Demo { // some …
Many think that abstract methods are waste and interfaces are still more waste. If you understand correctly, you find their immense usage. Let us see one on Java Interfaces. Suppose I would like to construct a house. I take the help of Java interfaces as follows. public interface Structure { public abstract void use53GradePortlandCement(); // …
Java coding comes with three types of classes – concrete classes, abstract classes and interfaces and comes with two keywords to inherit these classes – extends and implements. This tutorial is on how to use Java Interfaces with an example. Basically, Java does not support multiple inheritance and infact it is a drawback, says every …
An interface in Java gives a template of methods where the implementation or body for the methods is missing. The body or implementation is given by the sub classes in the way they think most appropriate. For example, I would like to prepare curry to take in my dinner. Imagine there is an interface as …
Java Interface in Java language play a very important role in Project designing. Very much useful for Architects. Interface gives a template of methods from which new classes can be developed easily. Basically, as every Learner says is, Java does not support multiple inheritance and also pointers. Not supporting multiple inheritance is a good drawback …
File class comes with many methods to know the properties of a file like canRead(), canWrite() etc. Following links illustrate with example code. 1. File class – Retrieving Metadata of File 2. File class – Changing File Properties
