OOP in Java Presentation.pptx
- 1. Hello! We are Team Quadra Our Group members are: Nafiz Ar Rafi (ID: 17182103359) Shohana Iasmin (ID: 17182103322) MD. Maruf Hossain (ID: Sinthia Sayeed (ID: Rokonuzzaman Razu (ID: 17182103211) 1
- 2. Presentation On Object Oriented programming (OOP)
- 3. Java OOP basic feature 1
- 4. Features of OOP Abstraction: In Java, abstraction means simple things like objects, classes and variables represent more complex underlying code and data. This is important because it lets you avoid repeating the same work multiple times. Encapsulation: The practice of keeping fields within a class private, then providing access to those fields via public methods. Encapsulation is a protective barrier that keeps the data and code safe within the class itself. Polymorphism: Allows programmers to use the same word in Java to mean different things in different contexts. One form of polymorphism is method overloading. The other form is method overriding. Inheritance: Inheritance is a special feature of Object- Oriented Programming in Java that lets programmers create new classes that share some of the attributes of existing classes. 4
- 5. “ 5 The simple abstraction example that is given above has a class Car. In this class Car, we have an abstract method to accelerate (). Then we inherit this class in the Suzuki class. Inside the Suzuki class, we implement the accelerated method. Example of Abstraction
- 6. Example of Encapsulation 6 Encapsulation is demonstrated as an OOP concept in Java. Here, the variable “name” is kept private or “encapsulated.”
- 7. 7 Example of Polymorphism In this example, we are creating two classes Bike and Splendor. Splendor class extends Bike class and overrides its run() method. We are calling the run method by the reference variable of Parent class. Since it refers to the subclass object and subclass method overrides the Parent class method, the subclass method is invoked at runtime
- 8. Example of Inheritance 8 In the above example, Programmer object can access the field of own class as well as of Employee class.
- 10. What are the Access modifiers? We can change the access level of fields, constructors, methods, and classes in Java programs by applying the access modifier to them. The access level refers to the accessibility or scope of a field, method, constructor, or class. 10 Access Modifi er
- 11. There are four types of java access modifiers 11 Private modifier: The access level of a private modifier is only within the class. It cannot be accessed from outside the class. Default modifier: The access level of a default modifier is only within the package. It cannot be accessed from outside the package. If you do not specify any access level, it will be the default. Protected modifier: The access level of a protected modifier is within the package and outside the package through child class. If you do not make the child class, it cannot be accessed from outside the package. Public modifier: The access level of a public modifier is everywhere. It can be accessed from within the class, outside the class, within the package and outside the package.
- 13. What is Java constructor and destructor? 13 A constructor is used to initialize a variable that means it allocates memory for the same A constructor is nothing but automatic initialization of the object. Whenever the program creates an object at that time constructor, is gets called automatically. You don’t need to call this method explicitly. On the other hand, Destructor is used to free that memory allocated during initialization. Generally, in java, we don’t need to call the destructor explicitly. Java has a feature of automatic garbage collection.
- 14. Why Constructor and destructor is needed? 14 Constructor and destructor are mostly used to handle memory allocation and de-allocation efficiently. Constructor and destructor do a very important role in any programming language of initializing and destroying it after use to free up the memory space.
- 16. What do Interface mean in java programming? 16 An interface is a programming structure/syntax that allows the computer to enforce certain properties on an object (class). For example: say we have a car class and a scooter class and a truck class. Each of these three classes should have a start_engine() action. How the "engine is started" for each vehicle is left to each particular class, but the fact that they must have a start_engine action is the domain of the interface.
- 18. What is Static Variable if we declare any variable as static, it is known as a static variable. 18 The static variable can be used to refer to the common property of all objects. For example, the company name of employees, University name of students, etc. It makes your program memory efficient
- 19. Let’s see how static variable in java is created 19
- 20. 6 Let's explain: We created a class called Student with three variables – studentName, course, and University. The first instance – Student1 – which has access to the variables created in its class had these values: Student1.studentName = “AB"; Student1.course = "Data Visualization"; Student1.University = “BUBT"; Second instance –Student2 - had these values: Student2.studentName = "CD"; Student2.course = "Data Analysis with Java"; As we declare University as a static variable that’s why we didn’t have to create its object in the second instance.
- 21. Diagram 21 Student -studentName: String -course: String -University: String Student1 +studentName: String +course: String +University: String Student2 +studentName: String +course: String Class: Student First Instance Class: Student1 Second Instance Class: Student2
- 22. 22 Explain: Student Class has this types of values – -studentName: String -course: String -University: String The first instance – Student1 – has these values- +studentName: String +course: String +University: String Second instance – Student2- has these values- +studentName: String +course: String
- 23. Thanks! That’s all from our side 23