Java IO Tutorial - Java Console

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The purpose of the Console class is to make the interaction between a Java program and the console easier.

The Console class is a utility class in the java.io package that gives access to the system console.

The console is not guaranteed to be accessible in a Java program on all machines. For example, if your Java program is run as a service, no console will be associated to the JVM.

We get the instance of the Console class by using the static console() method of the System class as follows:

Console console = System.console();
if (console != null) {
 console.printf("Console is available.")
}

The Console class has a printf() method that is used to display formatted string on the console. We also have a printf() method in the PrintStream class to write the formatted data.

The following code illustrates how to use the Console class.

The program prompts the user to enter a user name and a password. If the user enters password letmein, the program prints a message.

import java.io.Console;
/*fromwww.java2s.com*/
public class Main {
 public static void main(String[] args) {
 Console console = System.console();
 if (console != null) {
 console.printf("Console is available.%n");
 } else {
 System.out.println("Console is not available.%n");
 return; // A console is not available
 }
 String userName = console.readLine("User Name: ");
 char[] passChars = console.readPassword("Password: ");
 String passString = new String(passChars);
 if (passString.equals("letmein")) {
 console.printf("Hello %s", userName);
 } else {
 console.printf("Invalid password");
 }
 }
}

The code above generates the following result.

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