| 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. 
 | 
| Modifier and Type | Field and 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. 
 | 
| Modifier and Type | Method and Description | 
|---|---|
FileDescriptor | 
RandomAccessFile.getFD()
Returns the opaque file descriptor object associated with this
 stream. 
 | 
FileDescriptor | 
FileOutputStream.getFD()
Returns the file descriptor associated with this stream. 
 | 
FileDescriptor | 
FileInputStream.getFD()
Returns the  
FileDescriptor
 object  that represents the connection to
 the actual file in the file system being
 used by this FileInputStream. | 
| Constructor and 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 from. 
 | 
FileWriter(FileDescriptor fd)
Constructs a FileWriter object associated with a file descriptor. 
 | 
| Modifier and Type | Method and 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. | 
| Modifier and Type | Field and Description | 
|---|---|
protected FileDescriptor | 
DatagramSocketImpl.fd
The file descriptor object. 
 | 
protected FileDescriptor | 
SocketImpl.fd
The file descriptor object for this socket. 
 | 
| Modifier and Type | Method and Description | 
|---|---|
protected FileDescriptor | 
DatagramSocketImpl.getFileDescriptor()
Gets the datagram socket file descriptor. 
 | 
protected FileDescriptor | 
SocketImpl.getFileDescriptor()
Returns the value of this socket's  
fd field. | 
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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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