Module 4: Decision Making
`if` and `else`
Run one block when a condition is true and another block when it is false.
Author
Java Learner Editorial Team
Reviewer
Technical review by Java Learner
Last reviewed
2026-04-16
Java version
Java 25 LTS
Learning goals
- Write a basic `if` statement
- Add an `else` block for the fallback case
- Match conditions to simple everyday program rules
The if block: Java runs the code inside an if block only when the condition is true.
The else block: Use else for the fallback path when the if condition is false.
Why this matters: Once your program can choose between two paths, it starts behaving more like a real tool and less like a fixed script.
Keep branches small: In beginner code, short branches are easier to test and understand.
Runnable examples
Simple `if` / `else`
public class Main {
public static void main(String[] args) {
int age = 17;
if (age >= 18) {
System.out.println("Adult");
} else {
System.out.println("Not an adult");
}
}
}Expected output
Not an adult
Check a boolean variable
public class Main {
public static void main(String[] args) {
boolean hasTicket = true;
if (hasTicket) {
System.out.println("Entry allowed");
} else {
System.out.println("Entry denied");
}
}
}Expected output
Entry allowed
Common mistakes
Adding a semicolon right after the `if` condition
Write `if (condition) { ... }` without a semicolon after the closing parenthesis.
Mini exercise
Write an `if` / `else` that prints `Pass` when a score is at least 50 and `Try again` otherwise.
Summary
- `if` handles the true case.
- `else` handles the fallback case.
Next step
If two branches are not enough, chain multiple checks with `else if`.
Sources used