By the out.flush method, http header have been written to the response output
stream,
and also your html output. In spite of these operations your code  try to perform
another
operation like page forwarding. I suppose that you want to use servlet chains
and one
output excepted, created by 2 servlet operation. You have to include your second
servlet response into first servlet. Dont forward your request. If you have to
select
forward or not to forward than please donot generate any response output before
your decision point in your code. This means, technically, dont send http page
headers
to your client if you want to forward client request another servlet.

i hope these are helpfull 4 u...

I am not familiar with jsp  but just looking at the code  I can see one
possible problem. The out.flush() is probably causing your error. I took
this from the PrintStream class definition:

Optionally, a PrintStream can be created so as to flush automatically; this
means that the flush method is automatically invoked after a byte array is
written, one of the println methods is invoked, or a newline character or
byte ('\n') is written.

You must not print anything using the out.println
and then forward to another jsp,
maybe if you have conditional forward then it would work,
once the response is commited which you have done by calling flush you cannot
forward.
if(some condition)
{
print something
}else
{
forward
}
would work

then is there any way, so that i can display both the messages in the two jsp
pages by forwarding the request from one jsp  to other. Generally if i forward
from one jsp to other jsp file the message from the first jsp page is not
getting displayed while message in the second jsp file is getting displayed.

The problem  here is that you are trying to flush the buffer (out),
remove it and this will get flushed before the forward happens. Hope
this helps.