Reader ready() method in Java with Examples

The ready() method of Reader Class in Java is used to check whether this Reader is ready to be read or not. It returns a boolean which states if the reader is ready.

Syntax:

public void ready()

Parameters: This method does not accepts any parameters

Return Value: This method returns a boolean value which tells if this Reader is ready to be read or not. It return true if it is ready. Else it returns false.

Exception: This method throws IOException if some error occurs while input-output.

Below methods illustrates the working of ready() method:

Program 1:

// Java program to demonstrate
// Reader ready() method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {

            String str = "GeeksForGeeks";

            // Create a Reader instance
            Reader reader
                = new StringReader(str);

            // Check if the Reader is
            // ready to be read using ready()
            System.out.println("Is Reader ready "
                               + "to be read: "
                               + reader.ready());

            // Get the character
            // to be read from the stream
            int ch;

            // Read the first 5 characters
            // to this reader using read() method
            // This will put the str in the stream
            // till it is read by the reader
            for (int i = 0; i < 5; i++) {
                ch = reader.read();
                System.out.println("\nInteger value "
                                   + "of character read: "
                                   + ch);
                System.out.println("Actual "
                                   + "character read: "
                                   + (char)ch);
            }

            reader.close();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

Is Reader ready to be read: true

Integer value of character read: 71
Actual character read: G

Integer value of character read: 101
Actual character read: e

Integer value of character read: 101
Actual character read: e

Integer value of character read: 107
Actual character read: k

Integer value of character read: 115
Actual character read: s

Program 2:

// Java program to demonstrate
// Reader ready() method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {
            String str = "GeeksForGeeks";

            // Create a Reader instance
            Reader reader
                = new StringReader(str);

            reader.close();

            // Check if the Reader is
            // ready to be read using ready()
            System.out.println("Is Reader ready "
                               + "to be read: "
                               + reader.ready());

            // Get the character
            // to be read from the stream
            int ch;

            // Read the first character
            // to this reader using read() method
            // This will put the str in the stream
            // till it is read by the reader
            ch = reader.read();
            System.out.println("\nInteger value "
                               + "of character read: "
                               + ch);
            System.out.println("Actual "
                               + "character read: "
                               + (char)ch);

            reader.close();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

java.io.IOException: Stream closed

Reference: https://docs.oracle.com/javase/9/docs/api/java/io/Reader.html#ready–