Java Conditional Statements
if, else, else-if, switch

Conditional Statements in Java

Conditional statements allow your program to choose different paths of execution depending on whether a condition is true or false. Think of them as the 'brain' of your logic – making choices on your behalf.

Types of Conditional Statements in Java

Java provides several ways to handle conditions:

• if statement
• if-else statement
• else-if ladder
• switch statement

1. Java if Statement

The if statement checks a condition and executes the block of code inside it only if the condition is true.

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

The number is positive.

Explanation

The program checks if number > 0. Since 10 is greater than 0, it prints the message.

If the number were negative, nothing would be printed.

public class IfExample {
    public static void main(String[] args) {
        int number = -5;
        if (number > 0) {
            System.out.println("The number is positive.");
        }
    }
}

Explanation

The program checks if number > 0. Since -5 is not greater than 0, if block does not execute and nothing has been printed.

2. Java if-else Statement

Use this when you have two scenarios — one when the condition is true and another when it's false.

public class IfElseExample {
    public static void main(String[] args) {
        int number = -5;
        if (number >= 0) {
            System.out.println("Non-negative number");
        } else {
            System.out.println("Negative number");
        }
    }
}

Negative number

Since the given condition is false, else block executes.

This pattern is useful when your program must respond differently depending on a single true/false condition.

3. Java else-if Ladder

When you have multiple conditions to evaluate in a sequence, else-if ladders help maintain readability and logic flow.

public class ElseIfExample {
    public static void main(String[] args) {
        int score = 85;
        if (score >= 90) {
            System.out.println("Grade A");
        } else if (score >= 75) {
            System.out.println("Grade B");
        } else if (score >= 60) {
            System.out.println("Grade C");
        } else {
            System.out.println("Fail");
        }
    }
}

Grade B

Verification Tip

Start with the highest condition and work your way down to the least. This avoids overlapping ranges or incorrect classifications.

4. Java switch Statement

Use a switch when you have a single variable that can take multiple constant values (like enums, numbers, or strings in Java 7+).

public class SwitchExample {
    public static void main(String[] args) {
        int day = 3;
        switch (day) {
            case 1:
                System.out.println("Monday");
                break;
            case 2:
                System.out.println("Tuesday");
                break;
            case 3:
                System.out.println("Wednesday");
                break;
            default:
                System.out.println("Another day");
        }
    }
}

Wednesday

Important Checks

• Always include a break statement to prevent fall-through unless you want cumulative behavior.
• Include a default case to handle unexpected inputs.

Common Mistakes to Avoid

• Forgetting break in switch, which may lead to incorrect results.
• Using assignment = instead of comparison == in conditions.
• Improper nesting of if-else, leading to confusion and logic errors.

When to Use What?

Use Case	Statement Type
Single true/false condition	if
Binary decision path	if-else
Multiple ranges or tiers	else-if ladder
Discrete values for one variable	switch