OOPS in Java
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The document outlines the differences between procedural and object-oriented programming (OOP), emphasizing the characteristics, advantages, and key concepts of each paradigm. It highlights the benefits of OOP, such as code reuse, improved maintainability, and reduced development costs, while detailing concepts like classes, objects, inheritance, and encapsulation. Additionally, it provides a brief history and key features of the Java programming language, emphasizing its adaptability and object-oriented nature.
OOPS in Java
- 2. Characteristics: Emphasis is on doing things (algorithms) Large programs are divided into smaller functions Most of the functions share global data Data moves openly across the system from function to function Functions transform data from one form to another Uses top-down approach to program design Procedural Language(POP) - ex. ‘C’
- 3. Drawbacks: As functions openly access global data, new programmer could easily corrupt data accidentally Can easily access data from one function in another function, no protection! In large projects, it becomes difficult to identify what data is being used by which functions If program is modified to handle new data, all functions need to be modified to access data Functions transform data from one form to another Does not model real-time problems very well Procedural Languages - Drawbacks
- 4. Difference between POP & OOP’s
- 5. Top-down approach – ‘C’ Overview of system is formulated For each part; refine (+add) details Keep adding details everywhere until system is ready Large program broken into smaller functions Complex code Global data focused Limited; to no code reuse
- 6. Bottom-up approach – Java Describe entities then how they interact Start with concrete business case, proceed to implementation Easy to develop Unit test it here, and validate now Easy to change & modify later No duplication of code Reuse, wherever needed
- 7. Object Oriented - Advantages Code reuse & recycle Improved s/w development productivity Improved software maintainability Lesser development time Reduced cost of development Higher quality software Encapsulation
- 8. Object Oriented Concepts Class Object Inheritance Abstraction Encapsulation Polymorphism
- 9. Class – OO Concepts The basic unit of OOP’s is a ‘class’. Class encapsulates both the static attributes and dynamic behaviors within a "box“ Class combines “data structures” + “entity’s algorithm” A class is a blueprint from which objects get created. Class defines the state and behavior, typically, of a real- world object
- 10. Class – OO Concepts A class is a definition of objects of the same kind. Class is a blueprint, template, or prototype that defines and describes the static attributes and dynamic behaviors common to all objects of the same kind.
- 11. Object – OO Concepts An object is a realization of a particular item of a class. All instances (objects) of a class have same properties as in class definition Ex. Define a class called Student, create 3 instances: “Peter”, “Paul” & “Mary”.
- 12. Inheritance – OO Concepts Inheritance enables new objects to take on the properties of existing objects. A class that is used as the basis for inheritance is called a superclass or base class. A class that inherits from a superclass is called a subclass or derived class.
- 13. Abstraction – OO Concepts Hide internal details only show essential data about object to reduce complexity and increase efficiency Abstraction is selecting data from a larger pool to show only the relevant details of the object
- 14. Encapsulation – OO Concepts Also called ‘data binding’ Hide the state (value) of attributes within a class, preventing unauthorized direct access to it Control access to state of attributes + methods Bundling data and methods together in a class
- 15. Polymorphism – OO Concepts Generally, the ability to appear in many forms Ability to process objects differently depending on their data types or class Single interface to entities of different types Instances (subclass) derived from superclass Static @ compile time Dynamic @ run time
- 16. Compile & Run-time Polymorphism
- 17. Instance – OO Concepts An ‘instance’ is a unique copy of a class, that represents an object. When a new instance of a class is created, the JVM will allocate space in memory for that class instance. ‘Instance ‘and ‘object’ can be used interchangeably
- 18. State – OO Concepts An object has state (data) and behavior (functions). Is the instances (variables) inside the object that contains the data. State is the values of its attributes.
- 19. Attribute – OO Concepts An Attribute is a named property of a class. It has a type. It describes the range of values that this property may hold. A object can contain any number of attributes
- 20. Method (Operation) – OO Concepts The behaviour of an object is defined by its methods, which are the functions and subroutines defined within the object class. An operation that an object can perform.
- 21. Message Passing – OO Concepts Message passing is the communication between processes. Message passing is a form of communication used in object- oriented programming. Communications are completed by the sending of messages (functions and data) to recipients.
- 22. Generalization – OO Concepts The generalized entities contain the properties of all the generalized entities Also called as the ‘superclass’ Example: Pigeon, House sparrow, Crow and Dove can all be generalized as ‘Birds’.
- 23. Specialization – OO Concepts Specialization is the opposite of generalization. In specialization, a group of entities is divided into sub-groups based on their characteristics. For example: A ‘Person’ has name, date of birth, gender, etc. These properties are common in all persons, human beings. But in a company, persons can be identified as employee, employer, customer, or vendor, based on what role they play in the company.
- 24. History of Java 1990: ‘Oak’ To control microprocessors, embedded in customer products Oak needed to be: Platform Independent Extremely reliable Compact 1993: ‘Java’ Internet and web exploration Internet applications 1995: ‘Java 1.0’ James Gosling: Inventor of Java
- 25. Features of Java Compile & Interpret: Java compiler converts Java Source code into Java bytecode. Java interpreter converts bytecode into machine code Portable & Platform Independent: Java programs are easily transferred from one computer to another, bytecode interpreted on JVM Object Oriented: Java is 100% object oriented language Robust: Java supports automatic memory management and exception handling. Distributed: Has the ability to share & access data remotely
- 26. Features of Java Simple: Easy to understand syntax, doesn't support pointers, operator overloading, multiple inheritance Multithreaded: Java has the ability to write programs that do multiple tasks simultaneously Dynamic: Java allocates memory at runtime for classes, methods and objects as and when required
- 27. References https://www.javatpoint.com/java-oops-concepts https://beginnersbook.com/2013/04/oops-concepts/ https://www.guru99.com/java-oops-concept.html https://www.journaldev.com/12496/oops-concepts- java-example
- 28. Happy Oops Programming!! Thank you!