Re: Multiple HTTP async client instances and java.nio.channels.AsynchronousCloseException

[Sachin Nikumbh]

Hi Oleg,

Thanks for your response.

On Fri, Nov 16, 2012 at 10:59 AM, Oleg Kalnichevski <ol...@apache.org>wrote:

> On Thu, 2012-11-15 at 16:42 -0500, Sachin Nikumbh wrote:
> > Hi,
> >
> > I have successfully used the HTTP Async client. It's working great for
> the
> > most part. In my application I am creating multiple instances
> > of DefaultHttpAsyncClient. However, I
> > get java.nio.channels.AsynchronousCloseException once in a while with
> > following stack:
> >
> >
> ****************************************************************************************
> > ..............Nov 15, 2012 4:23:41 PM
> > org.apache.http.impl.nio.client.LoggingAsyncRequestExecutor exception
> > SEVERE: http-outgoing-3 [CLOSED] HTTP protocol exception: null
> > java.nio.channels.AsynchronousCloseException
> > at
> >
> java.nio.channels.spi.AbstractInterruptibleChannel.end(AbstractInterruptibleChannel.java:185)
> > at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:270)
> > at
> >
> org.apache.http.impl.nio.reactor.SessionInputBufferImpl.fill(SessionInputBufferImpl.java:97)
> > at
> >
> org.apache.http.impl.nio.codecs.AbstractMessageParser.fillBuffer(AbstractMessageParser.java:115)
> > at
> >
> org.apache.http.impl.nio.DefaultNHttpClientConnection.consumeInput(DefaultNHttpClientConnection.java:167)
> > at
> >
> org.apache.http.impl.nio.DefaultHttpClientIODispatch.onInputReady(DefaultHttpClientIODispatch.java:125)
> > at
> >
> org.apache.http.impl.nio.DefaultHttpClientIODispatch.onInputReady(DefaultHttpClientIODispatch.java:49)
> > at
> >
> org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:112)
> > at
> >
> org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:160)
> > at
> >
> org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:342)
> > at
> >
> org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:320)
> > at
> >
> org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:280)
> > at
> >
> org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:106)
> > at
> >
> org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:604)
> > at java.lang.Thread.run(Thread.java:662)
> >
> ****************************************************************************************
> >
> > Following is the snippet of how I am using an instance of
> > DefaultHttpAsyncClient in my code:
> >
> >
> ****************************************************************************************
> > HttpAsyncClient httpClientAsync = new DefaultHttpAsyncClient();
> > httpClientAsync.start();
> > final HttpPost postReq = new HttpPost(mpsUrl);
> > postReq.setEntity(new ByteArrayEntity(mlParams.toByteArray()));
> > final Future<HttpResponse> future = httpClientAsync.execute(postReq,
> null);
> > final HttpResponse response = future.get();
> > // DO SOMETHING WITH REPOSNSE
> > httpClientAsync.shutdown();
> >
> ****************************************************************************************
> >
> > Can the shutdown() call on one instance affect other instances
> > of DefaultHttpAsyncClient? Is there any global state that multiple
> > instances of DefaultHttpAsyncClient share that may be causing this
> problem?
> >
>
> No, it cannot, as long those instances do not share a common pool of
> connections.
>

Under what circumstances can I get into the situation where multiple
instances of DefaultHttpAsyncClient are sharing a common pool of
connections? If I am only using default DefaultHttpAsyncClient constructor
to create multiple instances, can I get myself into this situation without
realizing? The stack trace is making me believe so.



> I would recommend using only one instance of DefaultHttpAsyncClient per
> distinct HTTP service. Creating a new DefaultHttpAsyncClient instance
> for each and every request is enormously wasteful and inefficient.
>

I ended up with multiple DefaultHttpAsyncClient instances in the tests that
I was writing. I completely agree that creating
multiple DefaultHttpAsyncClient instances is wasteful and I do not intend
to do it in the final code.

Sachin