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Articles by Maruthi Krishna
Page 10 of 50
How to call another enum value in an enum's constructor using java?
Enumeration (enum) in Java is a datatype which stores a set of constant values. You can use enumerations to store fixed values such as days in a week, months in a year etc.You can define an enumeration using the keyword enum followed by the name of the enumeration as −enum Days { SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY }Methods and variables in an enumerationEnumerations are similar to classes and, you can have variables, methods (Only concrete methods) and constructors within them.For suppose we have elements in an enumeration with values as −enum Scoters { ACTIVA125(80000), ACTIVA5G(70000), ACCESS125(75000), ...
Read MoreDoes static factory method internally use new keyword to create object in java?
Factory pattern is a design pattern (creational pattern) which is used to create multiple objects based on the data we provide. In it we create an object abstracting the process of creation.ExampleBelow given is the example implementation of the factory pattern. Here, we have an interface with name Employee and 3 classes: Student, Lecturer, NonTeachingStaff, implementing it. We have created a factory class (EmployeeFactory) with a method named getEmployee(). This method accepts a String value and returns an object of one of the classes, based on the given String value.import java.util.Scanner; interface Person{ void dsplay(); } class Student implements ...
Read MoreHow static class Object is created without reference of outer class in java?
A static member (method/variable) belongs to the class and it will be loaded into the memory along with the class. You can invoke it without creating an object. (using the class name as reference). There is only one copy of the static field available throughout the class i.e. the value of the static field will be same in all objects. You can define a static field using the static keyword.Examplepublic class Sample{ static int num = 50; public static void demo(){ System.out.println("Value of num in the demo method "+ Sample.num); } } public class ...
Read MoreWhy static methods of parent class gets hidden in child class in java?
When we have two classes where, one extends another and if, these two classes have same method including parameters and return type (say, sample) the method in the sub class overrides the method in the super class.i.e. Since it is inheritance. If we instantiate the subclass a copy of superclass’s members is created in the subclass object and, thus both methods are available to the object of the subclass.But if you call the method (sample), the sample method of the subclass will be executed overriding the super class’s method.Exampleclass Super{ public static void sample(){ System.out.println("Method of ...
Read MoreHow to call a non-static method of an abstract class from a static method in java?
A method which does not have body is known as abstract method. It contains only method signature with a semi colon and, an abstract keyword before it.public abstract myMethod();To use an abstract method, you need to inherit it by extending its class and provide implementation to it.Abstract classA class which contains 0 or more abstract methods is known as abstract class. If it contains at least one abstract method, it must be declared abstract.Hence, if you want to prevent instantiation of a class directly, you can declare it abstract.Accessing non-static methods of an abstract classSince you cannot instantiate an abstract ...
Read MoreCan we make static reference to non-static fields in java?
A class in Java will have three kinds of variables namely, static (class), instance and, local.Local variables − These variables belong to and declared/defined within the methods/blocks/constructors. The scope of these variables lies within the method (or, block or, constructor) and will be destroyed after he execution of it.Instance variables − These variables belong to the instances (objects) of a class. These are declared within a class but outside methods. These are initialized when the class is instantiated. They can be accessed from any method, constructor or blocks of that particular class.You must access instance variables using an object. i.e. ...
Read MoreWhat is the syntax for passing Scanner object as a parameter in a method using java?
Until Java 1.5 to read data from the user programmers used to depend on the character stream classes and byte stream classes.From Java 1.5 Scanner class was introduced. This class accepts a File, InputStream, Path and, String objects, reads all the primitive data types and Strings (from the given source) token by token using regular expressions.By default, whitespace is considered as the delimiter (to break the data into tokens).To read various datatypes from the source using the nextXXX() methods provided by this class namely, nextInt(), nextShort(), nextFloat(), nextLong(), nextBigDecimal(), nextBigInteger(), nextLong(), nextShort(), nextDouble(), nextByte(), nextFloat(), next().Passing Scanner object as a ...
Read MoreHow to fix "Exception in thread main" in java?
An exception is an issue (run time error) occurred during the execution of a program. When an exception occurred the program gets terminated abruptly and, the code past the line that generated the exception never gets executed.Exampleimport java.util.Scanner; public class ExceptionExample { public static void main(String args[]) { Scanner sc = new Scanner(System.in); System.out.println("Enter first number: "); int a = sc.nextInt(); System.out.println("Enter second number: "); int b = sc.nextInt(); int c = a/b; System.out.println("The result is: "+c); ...
Read MoreCan we declare a static variable within a method in java?
A static filed/variable belongs to the class and it will be loaded into the memory along with the class. You can invoke them without creating an object. (using the class name as reference). There is only one copy of the static field available throughout the class i.e. the value of the static field will be same in all objects. You can define a static field using the static keyword.Examplepublic class Sample{ static int num = 50; public void demo(){ System.out.println("Value of num in the demo method "+ Sample.num); } public static void main(String ...
Read MoreHow and where does String literals in Java stored in the memory?
Strings are used to store a sequence of characters in Java, they are treated as objects. The String class of the java.lang package represents a String.You can create a String either by using the new keyword (like any other object) or, by assigning value to the literal (like any other primitive datatype).Examplepublic class StringDemo { public static void main(String args[]) { String stringObject = new String("Hello how are you"); System.out.println(stringObject); String stringLiteral = "Welcome to Tutorialspoint"; System.out.println(stringLiteral); } }OutputHello how are you Welcome to TutorialspointStorage of ...
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