Input from User

In Java, there are several ways to take input from the user. Here are some common methods.

1. Using Scanner Class: The Scanner class is a standard class in Java used for taking input from the user. It's part of the java.util package.

package src.main.java;

import java.util.Scanner;

public class Application {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter your name: ");
        String name = scanner.nextLine();
        System.out.println("Hello, " + name + "!");
        scanner.close();
    }
}

Among all the methods mentioned here, using the Scanner class is probably the most commonly used method for taking input from the user in Java, especially for beginner-level programming and simple console-based applications.

2. Using BufferedReader Class: The BufferedReader class, along with InputStreamReader, can be used to read input from the user. This method is useful when dealing with input streams. It's part of the java.io package.

package src.main.java;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Application {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter your age: ");
        int age = Integer.parseInt(reader.readLine());
        System.out.println("Your age is: " + age);
        reader.close();
    }
}

3. Using Command Line Arguments: You can also pass input arguments directly when running the program from the command line. These arguments can be accessed through the args parameter in the main method.

package src.main.java;

public class Application {
    public static void main(String[] args) {
        if (args.length > 0) {
            System.out.println("First argument: " + args[0]);
        } else {
            System.out.println("No arguments provided.");
        }
    }
}

4. Using Console Class (Java 6 and later): The Console class provides methods for reading input and writing output to the console. It is useful for simple console-based applications. It is a java.io package. Note that we need to execute the code via console.

package src.main.java;

import java.io.Console;

public class Application {
    public static void main(String[] args) {
        Console console = System.console();
        if (console != null) {
            String input = console.readLine("Enter your input: ");
            console.printf("You entered: %s\n", input);
        } else {
            System.out.println("Console is not available.");
        }
    }
}