Final and Static in Java Programming.pptx

Final and Static in Java Programming.pptx

• 1.
  Understanding 'final' and 'static' inJava Concepts, Uses, and Simple Examples
• 2.
  'final' Keyword in Java The 'final'keyword in Java is used to restrict modification: - **final variable**: Cannot be reassigned after initial assignment - **final method**: Cannot be overridden by subclasses - **final class**: Cannot be subclassed
• 3.
  Final Variable ReassignmentError public class FinalVariableExample { public static void main(String[] args) { final int x = 10; // Declare and initialize a final variable x = 20; // Error: Cannot assign a value to final variable 'x' } }
• 4.
  Final Method OverrideError class Animal { public final void makeSound() { System.out.println("Animal sound"); } } class Dog extends Animal { public void makeSound() { // Error: Cannot override the final method from Animal System.out.println("Bark"); } }
• 5.
  Final Class InheritanceError final class Vehicle { // class content } class Car extends Vehicle { // Error: Cannot subclass final class 'Vehicle' // class content }
• 6.
  'static' Keyword inJava • The 'static' keyword in Java is used to define class-level members: • - **Static Variable**: Shared among all instances of the class • - **Static Method**: Can be called without creating an object of the class • - **Static Block**: Executes once when the class is loaded
• 7.
  Static Variable class Counter{ static int count = 0; // static variable shared by all instances public void increment() { count++; // increments the static variable } public void showCount() { System.out.println("Count: " + count); } }
• 8.
  Static Variable public classMain { public static void main(String[] args) { Counter obj1 = new Counter(); Counter obj2 = new Counter(); Counter obj3 = new Counter(); obj1.increment(); obj1.showCount(); // Output: Count: 1 obj2.increment(); obj2.showCount(); // Output: Count: 2 obj3.increment(); obj3.showCount(); // Output: Count: 3 }}
• 9.
  Static Method OverrideError class Animal { public static void makeSound() { System.out.println("Animal sound"); } } class Dog extends Animal { @Override public void makeSound() { // Error: Static method in Animal cannot be overridden in Dog System.out.println("Bark"); } }
• 10.
  Static Class Nestedin Non-static Context static class OuterClass { // Error: Only inner classes can be declared static public void display() { System.out.println("Outer class display method"); } }
• 11.
  Final vs Static:Key Differences - **final**: - Immutability or prevention of change. - Applied to variables, methods, and classes. - **static**: - Class-level association, shared across all instances. - Applied to variables, methods, and blocks.
• 12.
  Summary In Java: - **final**keyword is used to restrict changes (variables, methods, and classes). - **static** keyword is used for shared class-level elements accessible without instance creation. Use these keywords carefully to optimize memory usage and maintain code stability.
• 13.
  Thank you foryour attention!