Java if-else Statement
Syntax and Examples

In Java, the if-else statement lets your program choose between different paths based on conditions. Imagine telling a story: if it rains, you stay home; otherwise, you go out. That’s if-else in action.

Syntax of if-else Statement

if (condition) {
    // Runs if condition is true
} else {
    // Runs if condition is false
}

• condition: This is a boolean expression that evaluates to either true or false.
• If the condition evaluates to true, the code block inside the if block runs.
• If the condition is false, the code block inside the else block runs instead.

Basic Example: Check if a Number is Positive

public class Main {
    public static void main(String[] args) {
        int number = 10;
        if (number > 0) {
            System.out.println("The number is positive.");
        }
    }
}

The number is positive.

Example with else: Even or Odd

public class Main {
    public static void main(String[] args) {
        int number = 7;
        if (number % 2 == 0) {
            System.out.println("Even number");
        } else {
            System.out.println("Odd number");
        }
    }
}

Odd number

Nested if Statements

Sometimes you want to check another condition only if the first one passes. That’s when nesting helps.

public class Main {
    public static void main(String[] args) {
        int age = 20;
        int score = 85;

        if (age >= 18) {
            if (score > 80) {
                System.out.println("Eligible for scholarship.");
            } else {
                System.out.println("Eligible, but no scholarship.");
            }
        } else {
            System.out.println("Not eligible.");
        }
    }
}

Eligible for scholarship.

Key Takeaways

• if checks a condition and runs code when it’s true.
• else provides an alternate path when the if fails.
• if-else-if allows multiple conditions to be checked in order.
• Nested if helps for dependent checks.

Real-world Example: Login Attempt

public class Main {
    public static void main(String[] args) {
        String username = "admin";
        String password = "1234";

        if (username.equals("admin")) {
            if (password.equals("1234")) {
                System.out.println("Login successful!");
            } else {
                System.out.println("Incorrect password.");
            }
        } else {
            System.out.println("Username not found.");
        }
    }
}

Login successful!