public final class FileDescriptor extends Object
FileInputStream or FileOutputStream to
 contain it.
 Applications should not create their own file descriptors.
FileInputStream, 
FileOutputStream| Modifier and Type | Field and Description | 
|---|---|
| static FileDescriptor | errA handle to the standard error stream. | 
| static FileDescriptor | inA handle to the standard input stream. | 
| static FileDescriptor | outA handle to the standard output stream. | 
| Constructor and Description | 
|---|
| FileDescriptor()Constructs an (invalid) FileDescriptor
 object. | 
| Modifier and Type | Method and Description | 
|---|---|
| void | sync()Force all system buffers to synchronize with the underlying
 device. | 
| boolean | valid()Tests if this file descriptor object is valid. | 
public static final FileDescriptor in
System.in.System.inpublic static final FileDescriptor out
System.out.System.outpublic static final FileDescriptor err
System.err.System.errpublic FileDescriptor()
public boolean valid()
true if the file descriptor object represents a
          valid, open file, socket, or other active I/O connection;
          false otherwise.public void sync()
          throws SyncFailedException
SyncFailedException - Thrown when the buffers cannot be flushed,
        or because the system cannot guarantee that all the
        buffers have been synchronized with physical media. Submit a bug or feature 
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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