What is the ‘if’ statement in Java and how to use it?

An if statement consists of a Boolean expression followed by one or more statements.

Syntax

Following is the syntax of an if statement −

if(Boolean_expression) {
   // Statements will execute if the Boolean expression is true
}

If the Boolean expression evaluates to true, then the block of code inside the if statement will be executed. If not, the first set of code after the end of the if statement (after the closing curly brace) will be executed.

Example

public class Test {
   public static void main(String args[]) {
      int x = 10;
      if( x < 20 ) {
         System.out.print("This is if statement");
      }
   }
}

Output

This is if statement.