FileDescriptor 

Introduction

The Java.io.FileDescriptor class instances serve as an opaque handle to the underlying machine-specific structure representing an open file, an open socket, or another source or sink of bytes. Following are the important points about FileDescriptor −

• The main practical use for a file descriptor is to create a FileInputStream or FileOutputStream to contain it.
• Applications should not create their own file descriptors.

Class declaration

Following is the declaration for Java.io.FileDescriptor class −

public final class FileDescriptor
   extends Object

Learn Java in-depth with real-world projects through our Java certification course. Enroll and become a certified expert to boost your career.

Field

Following are the fields for Java.io.FileDescriptor class −

• static FileDescriptor err − This is the handle to the standard error stream.
• static FileDescriptor in − This is the handle to the standard input stream.
• static FileDescriptor out − This is the handle to the standard output stream.

Class constructors

Sr.No.	Constructor & Description
1	FileDescriptor()This method constructs an (invalid) FileDescriptor object.

Class methods

Sr.No.	Method & Description
1	void sync()This method force all system buffers to synchronize with the underlying device.
2	boolean valid()This method tests if this file descriptor object is valid.

Methods inherited

This class inherits methods from the following classes −

• Java.io.Object