The Scanner class is part of the java.util class library. and it is used to get user input java.util.Scanner java.util.Scanner is a class in the Java API used to create a Scanner object, an extremely versatile object that you can use to input alphanumeric characters from several input sources and convert them to binary data. … Read more
A List is a linear structure where each element is known by an index number 0, 1, 2, … len-1 (like an array). Lists can only store objects, like String and Integer, but not primitives like int The List is probably the single most useful and widely used type of Collection. List is a general … Read more
An array in java is a data a structure used to process a collection of data that is all of the same type Other definition about Array in java An array is a flexible structure for storing a sequence of values all of the same type. A structure that holds multiple values of the same … Read more
Singleton class provides a static method to get its static instance to outside world. Singleton design pattern in java We can make constructor as private. So that We can not create an object outside of the class This property is useful to create singleton class in java. Singleton pattern helps us to keep only one … Read more
Polymorphism in Java is a concept by which we can perform a single action in different ways. Polymorphism is derived from 2 Greek words: poly and morphs. The word “poly” means many and “morphs” means forms. So polymorphism means many forms. There are two types of polymorphism in Java compile–time polymorphism runtime polymorphism Compile-time polymorphism … Read more
The final keyword in java is used to restrict the user. The java final keyword can be used in many context. Final can be variable method class The final keyword can be applied with the variables, a final variable that have no value it is called blank final variable or uninitialized final variable. It can … Read more
An interface in java is a blueprint of a class. It has static constants and abstract methods. The interface in java is a mechanism to achieve abstraction. There can be only abstract methods in the java interface not method body. It is used to achieve abstraction and multiple inheritance in Java. Java Interface also represents … Read more
A class that is declared with abstract keyword, is known as abstract class in java. It can have abstract and non–abstract methods (method with body) Abstraction in Java Abstraction is a process of hiding the implementation details and showing only functionality to the user Abstraction lets you focus on what the object does instead of … Read more
Inheritance in java is a relationship between a superclass: a more generalized class A subclass: a more specialized class The subclass ‘inherits’ data (variables) and behavior (methods) from the superclass Important facts about inheritance in Java Default superclass: Except Object class, which has no superclass, every class has one and only one direct superclass (single … Read more
Packages in java are those class which contains methods without the main method in them. Packages are mainly used to reuse the classes which are already created/used in other program We can define many number of classes in the same package Packages are mainly divided into two types Built in packages User defined Packages The … Read more