The class java.util.zip.DeflaterOutputStream subclasses OutputStream, but does not implement the flush method of OutputStream.  The default implementation of flush does nothing; hence, DeflaterOutputStream takes no action when told to flush.  However, the interface to OutputStream.flush clearly states: "...forces any buffered bytes to be written out."  DeflaterOutputStream buffers bytes in its Deflater  customer , but does not flush them when told to.  It only flushes when it is closed.

There is no workaround for this.  In JavaSafe, we actually link in zlib a second time to provide this functionality.

This requires support for partial flush in Deflater. Would be a nice thing
to have for FCS...

This has been fixed sometime ago. Now DeflaterOutputStream extends
FilterOutputStream, which flushes its underlying stream in 
FilterOutputStream.flush()


  xxxxx@xxxxx   2001-11-27

Please implement the flush method, even if it means implementing a new
FlushableDeflater class.  ZLIB provides this ability, but you haven't exposed
it.  In my application, I'm deflating a stream while sending it over a socket,
and the client side inflates the stream and draws graphics progressively.  Due
to the large internal buffer in Deflater, my application sends data in large
chunks, and the client side spends too much time waiting for the next large
chunk to arrive.  I want to flush the Deflater to send smaller chunks, which
will improve the apparent responsiveness of the client side.  Note that
although DeflaterOutputStream lets you control the size of *its* buffer, it
doesn't let you control the size of Deflater's internal buffer.

Is this bug related to 4206909?

This is a dupe of 4206909 indeed, how to add this to 4206909 list of related bugs?
It's a pity to separate votes on two duped bugs...