Oops concepts || Object Oriented Programming Concepts in Java
- 2. Topics for Today’s Session
- 3. Initially developed by James Gosling at Sun Microsystems and released in 1995. JAVA
- 4. Object Oriented Programming Object oriented Programming is a modern programming method to design a program using Classes and Objects Objects Real world entities that has their own properties and behaviours such as Book, Chair, Car, Pen, Table, etc., Class A class is a blueprint or prototype from which objects are created. Major objective is to eliminate unfavorable features encountered in Procedural approach
- 5. Procedural Vs Object Oriented ProgrammingProcedural Programming: It is known as POP Top Down Approach It deals with Algorithms Divided into functions It needs very less memory Doesn’s have Access Modifiers Data can move freely from function to function in the system It is Less Secure Example: C, Fortran Object Oriented Programming: It is known as OOP Bottom Up Approach It deals with data Divided into Objects It needs more memory that of POP Has Access Modifiers Objects can move & communicate with each other through member functions It is more Secure Example: C++, JAVA, C#
- 6. Object Oriented Paradigm features Emphasis is on data rather than procedure. Programs are divided into what are known as objects. Data structures are designed such that they characterize the objects. Methods that operate on the data of an object are tied together in the data structure. Data is hidden and cannot be accessed by external functions. Objects may communicate with each other through methods. New data and methods can be easily added whenever necessary. Follows bottom up approach in program design. First, the individual base elements of a program are specified. Then they are linked together to form larger sub sytems.
- 7. Applications of OOP Real-time systems Simulation and modeling Object-oriented databases Hypertext, hypermedia and expertext AI and expert systems Neural networks and parallel programming Decision support and office automation systems
- 8. What is Java? Java is a computing platform for application development and an object-oriented, Class-based and Concurrent programming language It means many statements can be executed at the same time instead of sequentially executing it. Java can run on all platforms and free to access. It is platform-independent Java is Simple, Secure, Robust, Complete Object oriented and Platform Independent High level Language It is Portable and Multi-thread technology gives High Performance. It supports concurrency means the code can be executed by multiple processes at the same time.
- 11. OOPS Concepts OBJECT ORIENTED PROGRAMMING (OOP) is a programming concept that works on the principles of abstraction, encapsulation, inheritance, and polymorphism It allows users to create the objects that they want and then, create methods to handle those objects. The basic concept of OOPs is to create objects, re-use them throughout the program, and manipulate these objects to get results. Object Oriented Programming popularly known as OOP, is used in a modern programming language like Java Object-oriented programming has several advantages over procedural programming: OOP is faster and easier to execute OOP provides a clear structure for the programs OOP helps to keep the Java code DRY "Don't Repeat Yourself", and makes the code easier to maintain, modify and debug OOP makes it possible to create full reusable applications with less code and shorter development time
- 12. OOP simplifies software development and maintenance by providing some concepts: 1. Object 2. Class 3. Inheritance 4. Polymorphism 5. Abstraction 6. Encapsulation 7. Dynamic Binding 8. Message Passing
- 13. Object: An instance of a class is known as a Object. Objects are the basic runtime entities in an object oriented system. Real world entity that has state and behavior . For example, a chair, pen, table, keyboard, bike, etc. It can be physical or logical. An object contains an address and takes up some space in memory. Each object contains data and code to manipulate the data. Representing an object
- 14. Class A class is a blueprint or prototype from which objects are created. Collection of objects. It is a logical entity not the physical entity The class is a group of similar entities. For example, if a class is “Expensive Cars” then objects like Mercedes, BMW, Toyota, etc. Its properties(data) can be - price, model or speed etc., Methods - driving, reverse, braking etc. Two instances of the class Student
- 15. Classes and objects are the two main aspects of object- oriented programming. So, a class is a template for objects, and an object is an instance of a class. When the individual objects are created, they inherit all the variables and methods from the class.
- 16. Data Abstraction Hiding internal details and showing functionality is known as abstraction. For example phone call, we don't know the internal processing. Abstraction refers to the act of representing essential features without including the background details or explanations. Classes use the concept of abstraction and they are known as abstract data types (ADT). Classes are defined as a list of abstract attributes such as size, weight and cost and methods that operate on these attributes. The technique of creating new data types that are well suited to an application to be programmed is known as Data Abstraction In Java, we use abstract class and interface to achieve abstraction.
- 17. Encapsulation Encapsulation means “Combining”. The wrapping up of data and methods into a single unit (called class) is known as Encapsulation. For example - in school, a student cannot exist without a class. Capsule
- 18. Inheritance Inheritance involves the creation of new classes (derived classes) from the existing ones ( base classes ). It is the process by which object of one class acquire the properties of another class. It supports the concept of hierarchical classification. Example: The bird Robin is a part of the class flying bird which is again a part of the bird Provides code reusability. Used to achieve runtime Polymorphism
- 19. o Single Inheritance refers to deriving a class from a single class. o A class is derived from more than one base class is known as Multiple inherence.
- 20. Polymorphism It is a Greek term, “Poly” means “many” and “morph” means “form”. Polymorphism means the ability to take more than one form. When one task is performed by different ways An operation may exhibit different behaviors in different instances. The behavior depends upon the types of data used in the operation.
- 21. There are 2 types of Polymorphism: 1. Compile-time Polymorphism (Method overloading / Static) 2. Runtime Polymorphism (Method Overriding / Dynamic) Method overloading Having multiple methods with same name but with different signature (number, type and order of parameters). Method Overriding When a subclass contains a method with the same name and signature as in the super class .
- 22. Dynamic Binding Binding refers the linking of a procedure call to the code to be executed in response to the call. Dynamic binding means that the code associated with a given procedure call is not known until the time of the call at runtime. It is associated with polymorphism & inheritance.
- 23. Message Passing A Message for an object is a request for execution of a procedure . It is the process of invoking an operation on an object. It involves the name of the object, the name of the method (message) and the information to be sent. For Example: Employee. salary (name); Here, Employee is the object, salary is the message and name is the parameter that contains information.
- 24. Summary
- 25. Conclusion In this lesson you learnt about Object Oriented Programming Procedural Vs Object Oriented Programming Object Oriented Paradigm Applications of OOP What is Java? OOPs Concepts