- Java Introduction
- Overview
- History and Evolution of Java
- Key Milestones
- Features of Java
- Java Development Kit (JDK) and Java Runtime Environment (JRE)
- Setting up the Java Development Environment
- Writing a Simple Java Program
- Understanding the Structure of a Java Program
- Java Fundamentals
- Variables and Data Types
- int
- float
- double
- char
- boolean
- Type Casting and Type Conversion in Java
- Type Casting
- Implicit casting (Widening Conversion)
- Explicit Casting (Narrowing Conversion)
- Type Conversion
- Implicit Conversion
- Explicit Conversion
- Important Points
- Operators
- Relational Operators
- Unary Operators
- Conditional Statements
- if Statement
- if-else Statement
- switch Statement
- Looping Statements
- for Loop
- while Loop
- do-while Loop
- Break and Continue Statements
- Arithmetic Operators
- Logical Operators
- Assignment Operators
- Java OOPS Concepts
- Classes and Objects
- Defining a Class
- Creating Objects
- Constructors
- This Keyword
- Methods
- Defining Methods
- Method Overloading
- Static Methods
- Encapsulation
- Access Modifiers
- Getters and Setters
- Inheritance
- Extending Classes
- Method Overriding
- super Keyword
- Example: Inheritance in an Animal Hierarchy
- Polymorphism
- Compile-Time Polymorphism (Method Overloading)
- Runtime Polymorphism (Method Overriding)
- Abstraction
- Abstract Classes and Methods
- Interfaces
- Java Advanced Concepts
- Arrays and Strings
- Single-Dimensional Arrays
- Multi-Dimensional Arrays
- The String Class and String Operations
- Exception Handling
- Types of Exceptions
- Try-Catch Block
- Finally Block
- Throw and Throws Keyword
- Custom Exceptions
- File I/O
- The File Class
- Handling File Exceptions
- Reading from a File
- Java Collections Framework
- Introduction to Collections
- Overview of the Collections Framework
- List Interface
- Set Interface
- Map Interface
- ArrayList and LinkedList
- ArrayList
- Creating and Using ArrayLists
- LinkedList
- Creating and Using LinkedLists
- HashSet and TreeSet
- HashSet
- Creating and Using HashSet
- TreeSet
- Creating and Using TreeSet
- HashMap and TreeMap
- HashMap
- Creating and Using HashMap
- TreeMap
- Creating and Using TreeMap
- Java GUI Programming
- Introduction to GUI Programming
- Overview of AWT and Swing
- Creating a Simple GUI Application Using Swing
- Components and Event Handling
- Common Swing Components
- Example: Creating a Simple GUI with Event Handling
- Java Project Development
- Developing a console-based a to-do list manager application
- Further Learning and Development
- Next Steps
- Conclusion
Example: Inheritance in an Animal Hierarchy
Example of Inheritance in an Animal Hierarchy in Java
| // Superclass public class Animal { // Fields protected String name; // Constructor public Animal(String name) { this.name = name; } // Method public void sound() { System.out.println("Animal makes a sound"); } // Method to display details public void displayDetails() { System.out.println("Name: " + name); } } // Subclass public class Dog extends Animal { // Additional field private String breed; // Constructor public Dog(String name, String breed) { super(name); // Call the constructor of the superclass this.breed = breed; } // Overriding the sound method @Override public void sound() { System.out.println("Dog barks"); } // Method to display details @Override public void displayDetails() { super.displayDetails(); // Call the superclass method System.out.println("Breed: " + breed); } public static void main(String[] args) { // Create an object of the Dog class Dog dog = new Dog("Buddy", "Golden Retriever"); // Display details dog.displayDetails(); // Call the sound method dog.sound(); } } |
The superclass Animal is identified by a field name, a constructor, a method named "sound," and a method named "displayDetails."
The subclass that extends the Animal class is the Dog class. It includes an additional field breed and a constructor that invokes the superclass constructor using the super keyword.
In order to implement a particular method, the Dog class overrides the sound method.
The Dog class's displayDetails method invokes the superclass's displayDetails method by calling super.displayDetails() and subsequently appends supplementary information.
The overridden sound method is executed, and an object of the Dog class is created and its details are displayed in the main method.
