Module 24: Static Keyword

⚙️ What is the static Keyword?

The static keyword in Java is used for memory management. It can be applied to variables, methods, blocks, and nested classes.

• Static Variable: Shared among all objects of the class.
• Static Method: Can be called without creating an object.
• Static Block: Runs once when the class is loaded.

📘 Examples

1. Static Variable

                    class Student {
                      int id;
                      String name;
                      static String college = "ABC College";  // shared by all instances
                    
                      Student(int i, String n) {
                        id = i;
                        name = n;
                      }
                    
                      void display() {
                        System.out.println(id + " " + name + " " + college);
                      }
                    }

2. Static Method

                    class MathUtil {
                      static int square(int x) {
                        return x * x;
                      }
                    }
                    
                    public class Main {
                      public static void main(String[] args) {
                        System.out.println(MathUtil.square(5));  // Outputs: 25
                      }
                    }
                    

3. Static Block

                    class Demo {
                      static {
                        System.out.println("Static block executed");
                      }
                    
                      public static void main(String[] args) {
                        System.out.println("Main method");
                      }
                    }
                    // Output:
                    // Static block executed
                    // Main method