BufferedWriter flush() method in Java with Examples

The flush() method of BufferedWriter class in Java is used to flush the characters from the buffered writer stream.

Syntax:

public void flush()
            throws IOException

Specified By: This method is specified by the flush() method of Flushable interface.

Overrides: This method overrides the flush() method of Writer class.

Parameters: This method does not accept any parameter.

Return value: This method does not return any value.

Exceptions: This method throws IOException if an I/O error occurs.

Below programs illustrate flush() method in BufferedWriter class in IO package:

Program 1:

// Java program to illustrate
// BufferedWriter flush() method

import java.io.*;

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

        // Create the string Writer
        StringWriter stringWriter
            = new StringWriter();

        // Convert stringWriter to
        // bufferedWriter
        BufferedWriter buffWriter
            = new BufferedWriter(
                stringWriter);

        // Write "GEEKS" to buffer writer
        buffWriter.write(
            "GEEKSFORGEEKS", 0, 5);

        // Flush the buffer writer
        buffWriter.flush();

        System.out.println(
            stringWriter.getBuffer());
    }
}

Output:

GEEKS

Program 2:

// Java program to illustrate
// BufferedWriter flush() method

import java.io.*;

public class GFG {
    public static void main(String[] args)
        throws IOException
    {
        // Create the string Writer
        StringWriter stringWriter
            = new StringWriter();

        // Convert stringWriter to
        // bufferedWriter
        BufferedWriter buffWriter
            = new BufferedWriter(
                stringWriter);

        // Write "GEEKS" to buffered writer
        buffWriter.write(
            "GEEKSFORGEEKS", 0, 5);

        // Flush the buffered writer
        buffWriter.flush();

        System.out.println(
            stringWriter.getBuffer());

        // Write "GEEKSFORGEEKS"
        // to buffered writer
        buffWriter.write(
            "GEEKSFORGEEKS", 5, 8);

        // Flush the buffered writer
        buffWriter.flush();

        System.out.println(
            stringWriter.getBuffer());
    }
}

Output:

GEEKS
GEEKSFORGEEKS

References:
https://docs.oracle.com/javase/10/docs/api/java/io/BufferedWriter.html#flush()