Conditions (if / else) in Java — Revision Notes

Definition

Syntax

if (condition) {
    // code
} else if (condition2) {
    // code
} else {
    // code
}

Example

public class Main {
    public static void main(String[] args) {
        int marks = 72;
        if (marks >= 90) {
            System.out.println("Grade: A");
        } else if (marks >= 60) {
            System.out.println("Grade: B");
        } else {
            System.out.println("Grade: C");
        }
    }
}

Output

Important Points

• Conditions must evaluate to a real boolean — Java won't accept an int directly.
• Traditional switch still needs break; in each case to avoid fall-through.
• The ternary operator works the same as in C/C++: a > b ? a : b.
• Nesting many if/else can often be simplified with switch or early returns.

Common Mistakes

• Forgetting break; in a traditional switch statement.
• Trying to use a non-boolean value directly as a condition.
• Comparing objects (like String) with == instead of .equals().

Interview Tip