# Class OutputStream

java.lang.Object
java.io.OutputStream

All Implemented Interfaces:
  `AutoCloseable`

Direct Known Subclasses:
  `BufferedOutputStream, ByteArrayOutputStream, DataOutputStream, FilterOutputStream, PrintStream`

public abstract class OutputStream extends Object implements AutoCloseable
This abstract class is the superclass of all classes representing an output stream of bytes. An output stream accepts output bytes and sends them to some sink. Applications that need to define a subclass of OutputStream must always provide at least a method that writes one byte of output. Since: JDK1.0, CLDC 1.0 See Also:ByteArrayOutputStream, DataOutputStream, InputStream, write(int)

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `OutputStream()`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `close()`
  Closes this output stream and releases any system resources associated with this stream.
  `void`
  `flush()`
  Flushes this output stream and forces any buffered output bytes to be written out.
  `void`
  `write(byte[] b)`
  Writes b.length bytes from the specified byte array to this output stream.
  `void`
  `write(byte[] b, int off, int len)`
  Writes len bytes from the specified byte array starting at offset off to this output stream.
  `abstract void`
  `write(int b)`
  Writes the specified byte to this output stream.

  ### Methods inherited from class Object

  `clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`
  Modifier and Type
  Method
  Description
  `protected Object`
  `clone()`
  `boolean`
  `equals(Object obj)`
  Indicates whether some other object is "equal to" this one.
  `final Class`
  `getClass()`
  Returns the runtime class of an object.
  `int`
  `hashCode()`
  Returns a hash code value for the object.
  `final void`
  `notify()`
  Wakes up a single thread that is waiting on this object's monitor.
  `final void`
  `notifyAll()`
  Wakes up all threads that are waiting on this object's monitor.
  `String`
  `toString()`
  Returns a string representation of the object.
  `final void`
  `wait()`
  Causes current thread to wait until another thread invokes the method or the method for this object.
  `final void`
  `wait(long timeout)`
  Causes current thread to wait until either another thread invokes the method or the method for this object, or a specified amount of time has elapsed.
  `final void`
  `wait(long timeout, int nanos)`
  Causes current thread to wait until another thread invokes the method or the method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.

- ## Constructor Details

  - ### OutputStream

    public OutputStream()

- ## Method Details

  - ### close

    public void close() throws IOException
    Closes this output stream and releases any system resources associated with this stream. The general contract of close is that it closes the output stream. A closed stream cannot perform output operations and cannot be reopened. The close method of OutputStream does nothing.
    Specified by:
      `close` in interface `AutoCloseable`
    Throws:
      `IOException`

  - ### flush

    public void flush() throws IOException
    Flushes this output stream and forces any buffered output bytes to be written out. The general contract of flush is that calling it is an indication that, if any bytes previously written have been buffered by the implementation of the output stream, such bytes should immediately be written to their intended destination. The flush method of OutputStream does nothing.
    Throws:
      `IOException`

  - ### write

    public void write(byte[] b) throws IOException
    Writes b.length bytes from the specified byte array to this output stream. The general contract for write(b) is that it should have exactly the same effect as the call write(b, 0, b.length).
    Throws:
      `IOException`

  - ### write

    public void write(byte[] b, int off, int len) throws IOException
    Writes len bytes from the specified byte array starting at offset off to this output stream. The general contract for write(b, off, len) is that some of the bytes in the array b are written to the output stream in order; element b[off] is the first byte written and b[off+len-1] is the last byte written by this operation. The write method of OutputStream calls the write method of one argument on each of the bytes to be written out. Subclasses are encouraged to override this method and provide a more efficient implementation. If b is null, a NullPointerException is thrown. If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown.
    Throws:
      `IOException`

  - ### write

    public abstract void write(int b) throws IOException
    Writes the specified byte to this output stream. The general contract for write is that one byte is written to the output stream. The byte to be written is the eight low-order bits of the argument b. The 24 high-order bits of b are ignored. Subclasses of OutputStream must provide an implementation for this method.
    Throws:
      `IOException`