Console readLine() method in Java with Examples (original) (raw)

Last Updated : 12 Jun, 2020

The readLine() method of Console class in Java is of two types: 1. The readLine() method of Console class in Java is used to read a single line of text from the console.Syntax:

public String readLine()

Parameters: This method does not accept any parameter.Return value: This method returns the string containing the line that is read from the console. It returns null if the stream has ended.Exceptions: This method throws IOError if an I/O error occurs.Note: System.console() returns null in an online IDE. Below programs illustrate readLine() method in Console class in IO package:Program 1:

Java `

// Java program to illustrate // Console readLine() method

import java.io.*;

public class GFG { public static void main(String[] args) { // Create the console object Console cnsl = System.console();

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

    // Read line
    String str = cnsl.readLine(
        "Enter string : ");

    // Print
    System.out.println(
        "You entered : " + str);
}

}

`

Output:

Program 2:

Java `

// Java program to illustrate // Console readLine() method

import java.io.*;

public class GFG { public static void main(String[] args) { // Create the console object Console cnsl = System.console();

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

    // Read line
    String str = cnsl.readLine(
        "Enter string : ");

    // Print
    System.out.println(
        "You entered : " + str);
}

}

`

Output:

2. The readLine(String, Object) method of Console class in Java is used to read a single line of text from the console by providing a formatted prompt.Syntax:

public String readLine(String fmt, Object... args)

Parameters: This method accepts two parameters:

• fmt - It represents the format of the string.
• args - It represents the arguments that are referenced by the format specifiers in the string format.

Return value: This method returns the string that contains the line read from the console. It returns null if the stream is ended.Exceptions:

• IllegalFormatException - This method throws IllegalFormatException if string format contains an illegal syntax or a format specifier is not compatible with the given arguments or insufficient arguments given the format string or other conditions that are illegal.
• IOError - This method throws IOError if an I/O error occurs.

Below programs illustrate readLine(String, Object) method in Console class in IO package:Program 1:

Java `

// Java program to illustrate // Console readLine(String, Object) method

import java.io.*;

public class GFG { public static void main(String[] args) { // Create the console object Console cnsl = System.console();

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

    String fmt = "%1$4s %2$10s %3$10s%n";

    // Read line
    String str
        = cnsl.readLine(
            fmt, "Enter", "string : ");

    // Print line
    System.out.println(
        "You entered : " + str);
}

}

`

Output:

Program 2: