Java - Console Class

Introduction

The Java Console class provides methods to access the character-based console device, if any, associated with the current Java virtual machine.

Class declaration

Following is the declaration for Java.io.Console class −

public final class Console
   extends Object
      implements Flushable

Class methods

Methods inherited

This class inherits methods from the following classes −

• Java.io.Object

Important Note

System.console() may return null in IDEs like Eclipse, NetBeans or IntelliJ. Run these programs from the command line (terminal) for proper execution.

Example - Ensuring Immediate Output Before a Delay

The following example shows the usage of Java Console flush() method. This example demonstrates using flush() to display text immediately before executing a time-consuming operation.

ConsoleDemo.java

package com.tutorialspoint;

import java.io.Console;

public class ConsoleDemo {
   public static void main(String[] args) {
      Console console = System.console();

      if (console != null) {
         // Print without newline and flush to ensure it's displayed immediately
         console.writer().print("Processing...");
         console.flush();  // Forces immediate display of "Processing..."

         // Simulating a long-running task
         try {
            Thread.sleep(3000); // Simulate 3 seconds delay
         } catch (InterruptedException e) {
            e.printStackTrace();
         }

         console.writer().println(" Done!"); // Completes the message
		 console.flush();
      } else {
         System.out.println("No console available.");
      }
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Processing... Done!

Explanation

• console.writer().print("Processing...") prints the text without a newline.

• console.flush() forces the buffer to flush, making "Processing..." visible immediately.

• A 3-second delay simulates a long-running operation.

• After completion, " Done!" is printed.

Example - Formatting and Displaying User Input

The following example shows the usage of Java Console format(String fmt, Object... args) method. This program prompts the user for their name and age, then formats and displays the input using format().

ConsoleDemo.java

package com.tutorialspoint;

import java.io.Console;

public class ConsoleDemo {
   public static void main(String[] args) {
      Console console = System.console(); // Get Console object

      if (console == null) {
         System.out.println("No console available.");
         return;
      }

      String name = console.readLine("Enter your name: ");
      int age = Integer.parseInt(console.readLine("Enter your age: "));

      console.format("Hello, %s! You are %d years old.%n", name, age);
   }
}

Console Interaction

Let us compile and run the above program, this will produce the following result −

Enter your name: Anil
Enter your age: 32
Hello, Anil! You are 32 years old.

Explanation

• The System.console() method is used to get a Console object.

• It checks if the console is available (to prevent errors in environments that don't support Console).

• The readLine() method is used to get the user's name and age as input.

• The format() method formats and displays the user's input in a structured way using format specifiers (%s for string, %d for integer).

Example - Printing Formatted User Details Using Console

The following example shows the usage of Java Console printf(String fmt, Object... args) method. This program prompts the user for their name and age and prints them in a formatted way using printf().

ConsoleDemo.java

package com.tutorialspoint;

import java.io.Console;

public class ConsoleDemo {
   public static void main(String[] args) {
      Console console = System.console(); // Get Console object

      if (console == null) {
         System.out.println("No console available.");
         return;
      }

      String name = console.readLine("Enter your name: ");
      int age = Integer.parseInt(console.readLine("Enter your age: "));

      console.printf("Hello, %s! You are %d years old.%n", name, age);
   }
}

Console Interaction

Let us compile and run the above program, this will produce the following result −

Enter your name: Kumar
Enter your age: 43
Hello, Kumar! You are 43 years old.

Explanation

• System.console() is used to get the Console object.

• readLine() is used to read the user's name and age.

• printf() formats and prints the message−

  • %s− String placeholder (for name).

  • %d− Integer placeholder (for age).

  • %n− Newline character.