Uses of Class java.io.FileDescriptor (Java SE 14 & JDK 14)
Description: use: module: java.base, package: java.io, class: FileDescriptor

# Uses of Class
java.io.FileDescriptor

Packages that use FileDescriptor
Package | Description
--- | ---
java.io | Provides for system input and output through data streams, serialization and the file system.
java.lang | Provides classes that are fundamental to the design of the Java programming language.
java.net | Provides the classes for implementing networking applications.
jdk.nio | Defines JDK-specific `channel` APIs.

- ## Uses of FileDescriptor in java.io

  Fields in java.io declared as FileDescriptor
  Modifier and Type | Field | Description
  --- | --- | ---
  `static FileDescriptor` | FileDescriptor.`err` | A handle to the standard error stream.
  `static FileDescriptor` | FileDescriptor.`in` | A handle to the standard input stream.
  `static FileDescriptor` | FileDescriptor.`out` | A handle to the standard output stream.

  Methods in java.io that return FileDescriptor
  Modifier and Type | Method | Description
  --- | --- | ---
  `FileDescriptor` | FileInputStream.`getFD()` | Returns the `FileDescriptor` object that represents the connection to the actual file in the file system being used by this `FileInputStream`.
  `FileDescriptor` | FileOutputStream.`getFD()` | Returns the file descriptor associated with this stream.
  `FileDescriptor` | RandomAccessFile.`getFD()` | Returns the opaque file descriptor object associated with this stream.

  Constructors in java.io with parameters of type FileDescriptor
  Constructor | Description
  --- | ---
  `FileInputStream​(FileDescriptor fdObj)` | Creates a `FileInputStream` by using the file descriptor `fdObj`, which represents an existing connection to an actual file in the file system.
  `FileOutputStream​(FileDescriptor fdObj)` | Creates a file output stream to write to the specified file descriptor, which represents an existing connection to an actual file in the file system.
  `FileReader​(FileDescriptor fd)` | Creates a new `FileReader`, given the `FileDescriptor` to read, using the platform's default charset.
  `FileWriter​(FileDescriptor fd)` | Constructs a `FileWriter` given a file descriptor, using the platform's default charset.

- ## Uses of FileDescriptor in java.lang

  Methods in java.lang with parameters of type FileDescriptor
  Modifier and Type | Method | Description
  --- | --- | ---
  `void` | SecurityManager.`checkRead​(FileDescriptor fd)` | Throws a `SecurityException` if the calling thread is not allowed to read from the specified file descriptor.
  `void` | SecurityManager.`checkWrite​(FileDescriptor fd)` | Throws a `SecurityException` if the calling thread is not allowed to write to the specified file descriptor.

- ## Uses of FileDescriptor in java.net

  Fields in java.net declared as FileDescriptor
  Modifier and Type | Field | Description
  --- | --- | ---
  `protected FileDescriptor` | DatagramSocketImpl.`fd` | The file descriptor object.
  `protected FileDescriptor` | SocketImpl.`fd` | The file descriptor object for this socket.

  Methods in java.net that return FileDescriptor
  Modifier and Type | Method | Description
  --- | --- | ---
  `protected FileDescriptor` | DatagramSocketImpl.`getFileDescriptor()` | Gets the datagram socket file descriptor.
  `protected FileDescriptor` | SocketImpl.`getFileDescriptor()` | Returns the value of this socket's `fd` field.

- ## Uses of FileDescriptor in jdk.nio

  Methods in jdk.nio with parameters of type FileDescriptor
  Modifier and Type | Method | Description
  --- | --- | ---
  `static SelectableChannel` | Channels.`readWriteSelectableChannel​(FileDescriptor fd, Channels.SelectableChannelCloser closer)` | Creates a selectable channel to a file descriptor that supports an `operation-set` of `OP_READ` and `OP_WRITE`.