Chapter 11
The java.io Package

ObjectOutput

Name

ObjectOutput

Synopsis

Interface Name:

java.io.ObjectOutput

Super-interface:

java.io.DataOutput

Immediate Sub-interfaces:

None

Implemented By:

java.io.ObjectOutputStream

Availability:

New as of JDK 1.1

The ObjectOutput interface extends the DataOutput interface for object serialization. While DataOutput defines methods for reading primitive types from a stream, ObjectOutput defines methods for writing objects and arrays of bytes.

Interface Declaration

public abstract interface java.io.ObjectOutput extends java.io.DataOutput {
  // Methods
  public abstract void close();
  public abstract void flush();
  public abstract void write(int b);
  public abstract void write(byte[] b);
  public abstract void write(byte[] b, int off, int len);
  public abstract void writeObject(Object obj);
}

Methods

close

public abstract void close() throws IOException

Throws

IOException: If any kind of I/O error occurs.

Description

This method closes the stream and releases any system resources associated with it.

flush

public abstract void flush() throws IOException

Throws

IOException: If any kind of I/O error occurs.

Description

If the stream uses a buffer, this method forces any bytes that may be buffered by the output stream to be written to the underlying physical device.

write

public abstract void write(int b) throws IOException

Parameters

b: The value to write.

Throws

IOException: If any kind of I/O error occurs.

Overrides

DataOutput.write(int)

Description

This method writes the lowest eight bits of the given integer b to the stream.

public abstract void write(byte[] b) throws IOException

Parameters

b: An array of bytes to write to the stream.

Throws

IOException: If any kind of I/O error occurs.

Overrides

DataOutput.write(byte[])

Description

This method writes all of the 8-bit bytes in the given array to the stream.

 public abstract void write(byte[] b, int off, int len) throws IOException

Parameters

b

An array of bytes to write to the stream.

off

An offset into the byte array.

len

The number of bytes to write.

Throws

IOException: If any kind of I/O error occurs.

Overrides

DataOutput.write(byte[], int, int)

Description

This method writes len bytes from the given array, starting off elements from the beginning of the array, to the stream.

writeObject

public abstract void writeObject(Object obj) throws IOException

Throws

IOException: If any kind of I/O error occurs.

Description

This method writes the given object to the stream, or in other words, it serializes an object to the stream. The class that implements this interface determines how the object is written.

Inherited Methods

Method	Inherited From	Method	Inherited From
`writeBoolean(boolean)`	`DataOutput`	`writeByte(int)`	`DataOutput`
`writeBytes(String)`	`DataOutput`	`writeChar(int)`	`DataOutput`
`writeChars(String)`	`DataOutput`	`writeDouble(double)`	`DataOutput`
`writeFloat(float)`	`DataOutput`	`writeInt(int)`	`DataOutput`
`writeLong(long)`	`DataOutput`	`writeShort(int)`	`DataOutput`
`writeUTF(String)`	`DataOutput`