Java If-Else Statements Explained for Beginners | Boolean Expressions Guide

Learn Java conditional statements step-by-step. Understand boolean expressions, relational and logical operators, and how if, else, and else-if work with beginner-friendly examples.

1. Pre-requisite: Boolean Expressions (Asking True/False Questions)

Before a program can make a decision, it needs to ask a question. In Java, these questions must always evaluate to a boolean value: either true or false.

To build these questions, we introduce two new sets of operators:

Relational Operators (Comparing Values)

Teacher’s Note: Remember the Golden Rule from Phase 2:

• = → assign a value (put the value in the box)
• == → compare two values (are these two the same?) Mixing these up is the #1 beginner bug.

Logical Operators (Combining Questions)

Sometimes one question isn’t enough. We use these to chain conditions together:

• && (AND) → true only if both sides are true
• || (OR) → true if at least one side is true
• ! (NOT) → flips true to false and false to true

2. The if Statement (The Basic Decision)

The if statement is the simplest way to make a decision.

• If the boolean expression inside () is true, Java runs the code inside {}.
• If it’s false, Java skips that block entirely.

int score = 85;

// Question: Is the score 80 or higher?
if (score >= 80) {
    System.out.println("You passed the test!");
}

3. The if-else Statement (The Backup Plan)

What if we want something specific to happen when the condition is false? That’s where else comes in.

• Guarantees that one of the two blocks runs, but never both.

boolean hasTicket = false;

if (hasTicket) {
    System.out.println("Welcome to the concert!");
} else {
    System.out.println("Sorry, you cannot enter."); 
}

Tip: In Java, if (hasTicket == true) can simply be written as if (hasTicket) — cleaner and easier to read.

4. The else if Chain (Multiple Options)

Life rarely has just two options. When you have several possibilities, use an else if chain.

• Java evaluates them from top to bottom.
• The first condition that is true runs, and the rest are skipped.

int temperature = 75;

if (temperature > 90) {
    System.out.println("It's boiling outside!");
} else if (temperature > 70) {
    // This runs because 75 > 70
    System.out.println("The weather is perfect.");
} else if (temperature > 50) {
    System.out.println("Bring a light jacket.");
} else {
    System.out.println("It is freezing!"); 
}

Tasks

Task

Look at this code. What will the program print out?

int age = 15;
boolean hasVIPPass = true;

if (age >= 18) {
    System.out.println("Come on in!");
} else if (hasVIPPass == true) {
    System.out.println("Right this way, VIP!");
} else {
    System.out.println("Sorry, come back when you are older.");
}

(Answer: It prints "Right this way, VIP!". The first condition (age >= 18) is false, so Java skips it. It checks the else if, which is true, runs that block, and then instantly skips the rest!)

📘 Related Topics

• Type Casting
• Loops