Java.io.FileInputStream.getFD() method is a part of Java.io.FileInputStream class. This method will return the FileDescriptor object associated with the file input stream.
- getFD() method is declared as final that means getFD() cannot be overridden in the subclasses
- FileDescriptor object that we will get using getFD() method will represent the connection to the actual file in the file system
- getFD() method might throw IOException.
Syntax:
public final FileDescriptor getFD() throws IOException
Return Type: getFD() method will return the instance of FileDescriptor associated with this FileInputStream.
Exception: getFD() method might throw IOException if any Input/output exception raises.
How to invoke getFD() method?
Step 1: First, we have to create an instance of Java.io.FileInputStream class
FileInputStream fileInputStream =new FileInputStream("tmp.txt");
Step 2: To get the instance of FileDescriptor associated with this fileInputStream, we will invoke the getFD() method
FileDescriptor fileDescriptor =fileInputStream.getFD();
Example: Java Program to get an instance of FileDescriptor and then to check it is valid or not
In the below program, we will
- use Java.io.FileInputStream.getFD() method to get the object of FileDescriptor
- use FileDescriptor valid() method to check if the instance of the file descriptor is valid or not
// Java Program to get an instance // of FileDescriptor and then to // check it is valid or not import java.io.*;
class GFG {
public static void main(String[] args)
{
try {
// create instance of FileInputStream class
// user should change name of the file
FileInputStream fileInputStream
= new FileInputStream(
// if the specified file does not exist
if (fileInputStream == null ) {
System.out.println(
"Cannot find the specified file" );
return ;
}
// to get the object of FileDescriptor for
// this specified fileInputStream
FileDescriptor fileDescriptor
= fileInputStream.getFD();
// check if the fileDescriptor is valid or not
// using it's valid method
// valid() will return true if valid else false
System.out.println( "Is FileDescriptor valid : "
+ fileDescriptor.valid());
// will close the file input stream and releases
// any system resources associated with the
// stream.
fileInputStream.close();
}
catch (Exception exception) {
System.out.println(exception.getMessage());
}
}
} |
Output:
Is FileDescriptor valid : true
Note: The programs will run on an online IDE. Please use an offline IDE and change the Name of the file according to your need.