Java if Statement Examples

The Java if statement tests the condition. It executes the if block if a condition is true.

Syntax

if(condition){  
//code to be executed  
}

Here, if statement may be a single statement or a compound statement enclosed in curly braces (that is, a block).

The statements get executed only when the given condition is true. If the condition is false then the statements inside if statement body is completely ignored.

Java if Statement Example

package net.javaguides.corejava.controlstatements.ifelse;

public class IfStatementExample {
    public static void main(String[] args) {
        int x, y;
        x = 10;
        y = 20;
        if (x < y) {
            System.out.println("x is less than y");
        }
        x = x * 2;
        if (x == y) {
            System.out.println("x now equal to y");
        }
        x = x * 2;
        if (x > y) {
            System.out.println("x now greater than y");
        }
        // this won't display anything
        if (x == y)
            System.out.println("you won't see this");
    }
}

Output:

x is less than y
x now equal to y
x now greater than y

Java Nested if Statement

When there is an if statement inside another if statement then it is called the nested if statement.

Syntex

if(condition_1) {
   Statement1(s);

   if(condition_2) {
      Statement2(s);
   }
}

Java Nested if Statement example

package net.javaguides.corejava.controlstatements.ifelse;

public class NetstedIfStatementExample {
    public static void main(String[] args) {
        int num = 50;
        if (num < 100) {
            System.out.println("number is less than 100");
            if (num == 50) {
                System.out.println("number equal to 50");
                if (num > 40) {
                    System.out.println("number is greater than 40");
                }
            }
        }
    }
}

Output:

number is less than 100
number equal to 50
number is greater than 40

Reference

1. Java if,if else,nested if, if else if Statement with Examples