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

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

Summary

Conditional statements bring your Java programs to life by adding the power of choice. They're the difference between rigid, robotic scripts and adaptive, intelligent logic. Start small with if, branch into else, scale with else-if, and simplify with switch.