Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

Console readLine() method in Java with Examples

  • 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.

Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

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 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 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 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:




// 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:

References:
1. https://docs.oracle.com/javase/10/docs/api/java/io/Console.html#readLine()
2. https://docs.oracle.com/javase/10/docs/api/java/io/Console.html#readLine(java.lang.String, java.lang.Object…)




My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!