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Java RandomAccessFile getFD() Method with Example

RandomAccessFile Class getFD() method: Here, we are going to learn about the getFD() method of RandomAccessFile Class with its syntax and example.
Submitted by Preeti Jain, on March 23, 2020

RandomAccessFile Class getFD() method

• getFD() method is available in java.io package.
• getFD() method is used to retrieve the file descriptor linked with this RandomAccessFile stream.
• getFD() 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.
• getFD() method may throw an exception at the time of returning the file channel.
  IOException: This exception may throw while performing input/output operation.

Syntax:

    public final FileDescriptor getFD();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of this method is FileDescriptor, it returns FileDescriptor object connected with this stream.

Example:

// Java program to demonstrate the example 
// of FileDescription getFD() method of
// RandomAccessFile

import java.io.*;

public class RAFGetFD {
 public static void main(String[] args) throws Exception {
  // Instantiate a random access file
  // object with file name and permissions
  RandomAccessFile ra_f = new RandomAccessFile("e:/includehelp.txt", "rw");

  // By using writeUTF() method is to 
  // write data in the file
  ra_f.writeUTF("Welcome, in Java World!!!");

  // Initially set the file pointer
  // is at 0 for reading the file
  ra_f.seek(0);

  // To read file content by using
  // readUTF()
  System.out.println("ra_f .readUTF(): " + ra_f.readUTF());

  // By using getFD() method is to
  // return the file descriptor linked with this
  // object
  System.out.println("ra_f.getFD(): " + ra_f.getFD());

  // By using close() method isto
  // close this stream ran_f
  ra_f.close();
 }
}

Output

ra_f .readUTF(): Welcome, in Java World!!!
ra_f.getFD(): java.io.FileDescriptor@ad3ba4