Re: Could this unclosed() byteArrayInputStream cause high Heap usage ?

Kevin McMurtrie <>
Fri, 05 Feb 2010 22:33:22 -0800
In article
 Krist <> wrote:

Hi all,

As part of our reporting integrated with our JSF/JSP application, the
report is converted to PDF then sent to browser for user to display.
mean while during peak load our Heap usage could reach 3.5GB - 4GB. So
I am suspecting the unclosed byteArrayInputStream is the cause.
(This is a production application so I am collecting information
before change the code)

Is the unclosed() byteArrayInputStream really cause the problem ?
(the codes is below)

Thank you,

ByteArrayInputStream byteArrayInputStream = (ByteArrayInputStream)
writeToBrowser(byteArrayInputStream, response, "application/csv",

private void writeToBrowser(ByteArrayInputStream byteArrayInputStream,
response, String mimetype, String exportFile)
   throws Exception {
      byte[] buffer = new byte[byteArrayInputStream.available()];
      int bytesRead = 0;
      response.setHeader("Content-disposition", "inline;filename=" +
      //Stream the byte array to the client.
      while((bytesRead = != -1)
            { response.getOutputStream().write(buffer , 0,

      //Flush and close the output stream.

This probably isn't where your memory is going. Turn on object
histogram dumps then send a QUIT signal when memory is high.

On the other hand, the code is bad:

Casting the InputStream to an implementation is prone to failure. Don't.

  byte[] buffer = new byte[byteArrayInputStream.available()];

InputStream.available() returns a value between 0 and the entire size of
the data. It's for avoiding blocking I/O and aligning buffers. It's
not for setting up a constant buffer size. In the case of
ByteArrayInputStream, it's the entire size of the data. Another
implementation might return zero and then you'd infinite loop. Use a
constant, like 2048 for WAN or 65536 for LAN.

If the PrintOutputController belongs to you, consider modifying it to
write directly to an OutputStream. This will eliminate intermediate
buffering and provide a faster first-byte response. The downside is
that the PrintOutputController could be active and holding resources for
a very long time if the client is on dialup. Which is best depends on
the application.
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