Home » Java programming language

Java FilterOutputStream flush() Method with Example

FilterOutputStream Class flush() method: Here, we are going to learn about the flush() method of FilterOutputStream Class with its syntax and example.
Submitted by Preeti Jain, on April 02, 2020

FilterOutputStream Class flush() method

• flush() method is available in java.io package.
• flush() method is used to flush this FilterOutputStream and forces bytes to be written out of any buffered data to the FilterInputStream.
• 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 when getting any input/output error.

Syntax:

    public void flush();

Parameter(s):

• It does not accept any parameter.

Return value:

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

Example:

// Java program to demonstrate the example 
// of void flush() method of FilterInputStream

import java.io.*;

public class FlushOfFOS {
 public static void main(String[] args) throws Exception {
  FileInputStream fis_stm = null;
  FilterInputStream fil_stm = null;
  FileOutputStream fos_stm = null;
  FilterOutputStream fol_stm = null;

  int count = 0;

  try {
   // Instantiates FileOutputStream and 
   // FilterOutputStream
   fos_stm = new FileOutputStream("D:\\includehelp.txt");
   fol_stm = new BufferedOutputStream(fos_stm);

   // By using write() method is to
   // write byte to the fol_stm stream
   fol_stm.write(97);

   // By using flush() method is to
   // write bytes out to the basic 
   // output stream
   fol_stm.flush();

   // Instantiates FileInputStream and 
   // FilterInputStream
   fis_stm = new FileInputStream("C:\\Users\\Preeti Jain\\Desktop\\programs\\includehelp.txt");
   fil_stm = new BufferedInputStream(fis_stm);

   // Loop to read until available
   // bytes left
   while ((count = fil_stm.read()) != -1) {
    // Display corresponding bytes value
    char ch = (char) count;
    // Display value of b
    System.out.println("ch: " + ch);
   }
  } catch (Exception ex) {
   System.out.println(ex.toString());
  } finally {
   // with the help of this block is to
   // free all necessary resources linked
   // with the stream

   if (fis_stm != null) {
    fis_stm.close();

    if (fil_stm != null) {
     fil_stm.close();

     if (fol_stm != null) {
      fol_stm.close();

      if (fos_stm != null) {
       fos_stm.close();
      }
     }
    }
   }
  }
 }
}

Output

ch: a