Concepts of Computer Science

Difference between Abstract Class and Interface Difference between abstract class and interface ? Abstract Class:- 1) Can have abstract and non-abstract method both. 2) One class can extend at most one class. 3) can declare non abstract method and also can define body for it. Interface:- 1) can have only abstract method. 2) One class can implement multiple interfaces. 3) can't delare body to a method. Please look below example for more understanding:- package Basics ; public abstract class Animal { int head ; //no body (unimplemented function need to override in child class as a //compulsion abstract void setLegs (); //having body //may override or may not void setHead () { head =1; } } package Basics ; // can have only methods and by default all are abstract need to be override //by implementing class, unlike abstract no method can havedefinition public interface Pet { void tellWhereAreYouFr...

Basics of java in layman term for beginner What is an object ? object is a real world entity. Object is an instance of the class.It means something that is alive. Let us take an example of CAR:- concept of a car is class. I mean we all know that it is having four tyres , one engine , four doors , a seat e.t.c. but we can't do anything just by the concept we need real Car to perform operations on it . This real car is what we call is an object. Explain about main() method in java ? main() method is an entry point of a program. public static void main(String[] args) Why main() method is public, static and void in java ? public: It can be accessed from anywhere. static: no class object need to call this method. void: it is not returning anything in back. What is JIT compiler ? JIT is just in time compiler.JIT compiler runs after the program has started and compiles the code (usually bytecode or some kind of VM instructions) on the fly (or just-...

How to build a project in eclipse with MAVEN build tool? Step 1:- Install maven and set the path in my computer. Once path is set for java and maven you will get a screen With version installed in your system. Step 2:- Write a command mvn archetype:generate to build a project of your choice.This will give you a option to select a project from list. Step 3:- As soon as this operation will complete maven give you choice to choose project.Search for maven-archetype-webapp this will build a web project with basic structure. Step4:- Follow the below procedure to give name , version ,package ,artifact and group id of your choice. Step 5:- You will get screen with build success.Congrats your project is build in directory. Step 6: Go in the directory to check for the folders automatically created by maven. You will get pom file and src folder and the package folder. Step:-7  Move to the directry having pom.xml and run mvn...