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| Chapter 24 The java.io Package |

## 24.17 java.io.FileDescriptor (JDK 1.0)

###

This class is a platform-independent representation of a low-level handle to an open file or an open socket. The static `in`, `out`, and `err` variables are `FileDescriptor` objects that represent the system standard input, output, and error streams, respectively. There is no public constructor method to create a `FileDescriptor` object. You can obtain one with the `getFD()` method of `FileInputStream`, `FileOutputStream`, and `RandomAccessFile`.

    public final class FileDescriptor extends Object {
        // Default Constructor: public FileDescriptor()
        // Constants
                public static final FileDescriptor err;
                public static final FileDescriptor in;
                public static final FileDescriptor out;
        // Public Instance Methods
            1.1  public native void sync() throws SyncFailedException;
                public native boolean valid();
    }

### Passed To:

FileInputStream(), FileOutputStream(), FileReader(), FileWriter(), SecurityManager.checkRead(), SecurityManager.checkWrite()

### Returned By:

DatagramSocketImpl.getFileDescriptor(), FileInputStream.getFD(), FileOutputStream.getFD(), RandomAccessFile.getFD(), SocketImpl.getFileDescriptor()

### Type Of:

DatagramSocketImpl.fd, FileDescriptor.err, FileDescriptor.in, FileDescriptor.out, SocketImpl.fd

java.io.File (JDK 1.0) |  | java.io.FileInputStream (JDK 1.0)