CS & BCA Notes

  IMPLEMENTATION OF INHERITANCE What is Inheritance ? Ø   The process by which one class acquires the properties(data members) and functionalities(methods) of another class is called  inheritance . Ø   The aim of inheritance is to provide the reusability of code so that a class has to write only the unique features and rest of the common properties and functionalities can be extended from the another class. Aim:             To write a java program to implement the concept of inheritance. Procedure: Open text editor(notepad) Create a base class called “StudentBase” Declare & define department, collegeName as private data members of string datatype. Since the private data members cannot be   accessed directly, we are using public getter & setter methods   to access the private members of base class Create a derived class called “StudentDerive” that extends the base class “StudentBase” Declare & define regNo, sName as default data members of string datatype.  

  IMPLEMENTATION OF CLASS & OBJECTS College.java import java.io.*; public class College {             String name;             String dept;             int age;             String place;             public College(String name, String dept,int age, String place)             {                         this.name = name;                         this.dept = dept;                         this.age = age;                         this.place = place;             }             public String getName()             {                         return name;             }             public String getDept()             {                         return dept;             }             public int getAge()             {                         return age;             }                public String getPlace()             {                         return place;             } public String display()             { return("Name :"+ t

    II BCA -  CORE PAPER 3 PROGRAMMING IN JAVA USE INTERFACES Contents: Java Interface Need for Java interface Declaring an Interface Relationship between Interface & class Declaring Interface Constants  Java Interface ·          The interface in Java is  a mechanism to achieve  abstraction that specify what a class must do  without saying anything about how the class will do it. ·          An interface can be defined as a container that stores the methods to be implemented in the code segment. ·          An interface can have methods and variables just like the class but the methods declared in interface are by default abstract. ·          The variables declared in an interface are public, static & final by default. Need for Java interface There are mainly three reasons to use interface. 1.        It is used to achieve abstraction. 2.       By interface, we can support the functionality of multiple inheritances. 3.       It can be used to achieve lo