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Java BufferedWriter flush() Method with Example

BufferedWriter Class flush() method: Here, we are going to learn about the flush() method of BufferedWriter Class with its syntax and example.
Submitted by Preeti Jain, on March 01, 2020

BufferedWriter Class flush() method

• flush() method is available in java.io package.
• flush() method is used to flushes the characters from a write buffer to the character or byte stream.
• flush() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• flush() method may throw an exception at the time of flushing the stream.
  IOException: This exception may throw an exception while performing input/output operation.

Syntax:

    public Writer flush();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is Writer, it returns nothing.

Example:

// Java program to demonstrate the example 
// of Writer flush() method of
// BufferedWriter

import java.io.*;

public class FlushBW {
    public static void main(String[] args) {
        String str = "Java Programming";
        try {
            // Instantiates StringWriter
            StringWriter str_w = new StringWriter();

            // Instantiates BufferedWriter
            BufferedWriter buff_w = new BufferedWriter(str_w);

            for (char ch: str.toCharArray()) {
                // To append character by using
                // append() to the writer
                buff_w.append(ch);

                // It flushes the characters
                // from buff_w to char or byte
                // stream
                buff_w.flush();

                // Display Buffer from str_w
                System.out.println("str_w.getBuffer():" + str_w.getBuffer());
            }

            // Close the stream
            buff_w.close();

        } catch (IOException ex) {
            System.out.println("buff_w: " + ex.getMessage());
        }
    }
}

Output

str_w.getBuffer():J
str_w.getBuffer():Ja
str_w.getBuffer():Jav
str_w.getBuffer():Java
str_w.getBuffer():Java 
str_w.getBuffer():Java P
str_w.getBuffer():Java Pr
str_w.getBuffer():Java Pro
str_w.getBuffer():Java Prog
str_w.getBuffer():Java Progr
str_w.getBuffer():Java Progra
str_w.getBuffer():Java Program
str_w.getBuffer():Java Programm
str_w.getBuffer():Java Programmi
str_w.getBuffer():Java Programmin
str_w.getBuffer():Java Programming