Reader read() method in Java with Examples

The read() method of Reader Class in Java is used to read a single character from the stream. This method blocks the stream till:

  • It has taken some input from the stream.
  • Some IOException has occurred
  • It has reached the end of the stream while reading.

This method is declared as abstract method. It means that the subclasses of Reader abstract class should override this method if desired operation needs to be changed while reading a character.

Syntax:

public abstract int read()

Parameters: This method does not accepts any parameters

Return Value: This method returns an integer value which is the integer value read from the stream. It can range from 0 to 65535. Else it returns -1 if no character has been read.

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

Below methods illustrates the working of read() method:

Program 1:

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// Java program to demonstrate
// Reader read() 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);
  
            // 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);
        }
    }
}

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Output:

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:

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// Java program to demonstrate
// Reader read() 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);
  
            // 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);
        }
    }
}

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Output:

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

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



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