Input & Output in Java

Q: What is Input & Output in Java?

Java prints output with System.out.println() (or print() without a newline).

Input & Output

Java prints output with System.out.println() (or print() without a newline). For reading input from the keyboard, Java uses the Scanner class from java.util.

💡 Key insight You must import java.util.Scanner before you can read keyboard input in Java — it's not available by default like println is.

Syntax

syntax

import java.util.Scanner;
Scanner sc = new Scanner(System.in);
int x = sc.nextInt();
String s = sc.nextLine();

Example

sc.nextInt() reads a whole number typed by the user and returns it as an int.

java

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter your age: ");
        int age = sc.nextInt();
        System.out.println("You are " + age + " years old.");
    }
}

outputEnter your age: 20 You are 20 years old.