Hi there, One of my applications is facing a pesky issue in Tomcat 8.0.15 dealing with an NPE at InternalNioOutputBuffer.java:234.
I searched Bugzilla and the lists, but didn't find anything that matched the NPE stack exactly. Maybe I missed it. Before I file a bug, I wanted to check here first. Here's the stack trace: java.lang.NullPointerException: null at org.apache.coyote.http11.InternalNioOutputBuffer.flushBuffer(InternalNioOutputBuffer.java:234) ~[tomcat-coyote.jar:8.0.15] at org.apache.coyote.http11.InternalNioOutputBuffer.addToBB(InternalNioOutputBuffer.java:189) ~[tomcat-coyote.jar:8.0.15] at org.apache.coyote.http11.InternalNioOutputBuffer.commit(InternalNioOutputBuffer.java:177) ~[tomcat-coyote.jar:8.0.15] at org.apache.coyote.http11.AbstractHttp11Processor.action(AbstractHttp11Processor.java:739) ~[tomcat-coyote.jar:8.0.15] at org.apache.coyote.Response.action(Response.java:179) ~[tomcat-coyote.jar:8.0.15] at org.apache.coyote.http11.AbstractOutputBuffer.doWrite(AbstractOutputBuffer.java:249) ~[tomcat-coyote.jar:8.0.15] at org.apache.coyote.Response.doWrite(Response.java:503) ~[tomcat-coyote.jar:8.0.15] at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:388) ~[catalina.jar:8.0.15] at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:426) ~[tomcat-util.jar:8.0.15] at org.apache.catalina.connector.OutputBuffer.writeBytes(OutputBuffer.java:424) ~[catalina.jar:8.0.15] at org.apache.catalina.connector.OutputBuffer.write(OutputBuffer.java:406) ~[catalina.jar:8.0.15] at org.apache.catalina.connector.CoyoteOutputStream.write(CoyoteOutputStream.java:97) ~[catalina.jar:8.0.15] at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:221) ~[na:1.7.0_71] at sun.nio.cs.StreamEncoder.implClose(StreamEncoder.java:316) ~[na:1.7.0_71] at sun.nio.cs.StreamEncoder.close(StreamEncoder.java:149) ~[na:1.7.0_71] at java.io.OutputStreamWriter.close(OutputStreamWriter.java:233) ~[na:1.7.0_71] at foo.bar.NioNPETestServlet$ServletRunnable.run(NioNPETestServlet.java:90) ~[NioNPETestServlet$ServletRunnable.class:na] at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [na:1.7.0_71] at java.util.concurrent.FutureTask.run(FutureTask.java:262) [na:1.7.0_71] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_71] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_71] at java.lang.Thread.run(Thread.java:745) [na:1.7.0_71] I spent some time and whittled down the use case into a single servlet that reproduces the problem quite easily with curl: while true; do curl -v -X GET http://localhost:8080/npe; done Here's the servlet and other goodies via Gist: https://gist.github.com/markkolich/7cd972292418a58b5ef5 And here's a runnable version of the servlet wrapped in Tomcat 8.0.15: http://koli.ch/x5iu Note in addition to the NPE above, some request/responses complete, but with a corrupted response buffer: < HTTP/1.1 401 HTTP/1.1 401 UnauthorizeUnauthorized * no chunk, no close, no size. Assume close to signal end < Server: Apache-Coyote/1.1 json;charset=utf-8 ContentContent-Type Date: Tue,:: application/json;charset=utf-8 application/json;charset=utf-8 : 0 Content-Length: 0 : Date: I suspect the corruption and NPE are related. The trouble servlet is fairly vanilla, or so I think. The service() method is invoked, I grab a new AsyncContext for the request, and pass it off to a runnable in a pool for processing. The runnable sets the HTTP response code to 401, and writes out a string of JSON. The OutputStreamWriter used to write the response is flushed/closed when execution leaves the try-with-resources block. My understanding is that closing the OutputStreamWriter here also closes the underlying ServletOutputStream, but I don't think there's anything wrong with that. I'm completing the AsyncContext immediately following that flush/close and I'm done -- I don't intend to use the ServletOutputStream again, and even if Tomcat itself calls close() on this same stream again later, this subsequent call to close() should have no effect. I also tried setting `-Dorg.apache.catalina.connector.RECYCLE_FACADES=true` which didn't help at all. Other details: Java 7 u71 x64 Linux (CentOS 6.6) If you have any thoughts on what I'm doing wrong, or if you can confirm this is a legit bug, I'd be grateful for your input. Thanks for your help, -Mark
