How to Use If Else in Java: Simple Guide with Examples

In Java, use the if statement to run code only when a condition is true, and else to run code when it is false. The syntax is if (condition) { ... } else { ... }, where the condition is a true/false check.

Syntax

The if else statement lets you choose between two paths based on a condition.

• if (condition): Checks if the condition is true.
• { ... }: Code inside runs if condition is true.
• else: Runs if the condition is false.
• { ... }: Code inside runs if condition is false.

java

if (condition) {
    // code runs if condition is true
} else {
    // code runs if condition is false
}

Example

This example checks if a number is positive or not and prints a message accordingly.

java

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

Output

The number is positive.

Common Pitfalls

Common mistakes include missing braces, using = instead of == for comparison, and forgetting the else block when needed.

Always use braces { } to avoid confusion, even for single statements.

java

/* Wrong: Using = instead of == */
if (number == 5) {
    System.out.println("This is wrong");
}

/* Right: Use == for comparison */
if (number == 5) {
    System.out.println("This is correct");
}

Quick Reference

Part	Description
if (condition)	Checks if condition is true
{ ... }	Code block for true condition
else	Runs if condition is false
{ ... }	Code block for false condition

Key Takeaways

Use if else to run different code based on true or false conditions.

Always use == to compare values, not = which assigns values.

Include braces { } to clearly define code blocks for if and else.

The else block is optional but useful for handling the false case.

Test your conditions carefully to avoid logic errors.