Does closing a BufferedOutputStream also close the underlying OutputStream?

Question

I am streaming binary data (a CSV file extracted from the database as a Clob) to the browser by calling response.getOutputStream() and would normally wrap the OutputStream in a

Answer 1

Closing the BufferedOutputStream will also close the underlying OutputStream. You should close the BufferedOutputStream so that it flushes its contents before closing the underlying stream. See the implementation of FilterOutputStream.close() (from which BufferedOutputStream extends) to convince yourself.

I guess that whether or not the response stream given to your servlet is buffered or not depends on the implementation of your Servlet Container. FWIW I know that Tomcat does buffer its servlet response streams by default, in order to attempt to set the content-length HTTP header.