Kafka on Windows - start service error - windows

Question

I am trying to cleanly start Kafka 2.10 - 0.8.2.1 on Windows but I am getting an annoying error everytime I start it.
I have just installed Kafka by following the Quick Start guide (with the exception that I have installed Zookeeper myself). Both Kafka and Zookeeper were installed very basic, on a single machine.
Problem
When I run the starting script:
kafka-server-start.bat C:\kafka_2.10-0.8.2.1\config\server.properties
I get the error:
Error
[2015-07-14 17:00:45,197] WARN Error when freeing index buffer (kafka.log.OffsetIndex)
java.lang.NullPointerException
at kafka.log.OffsetIndex.kafka$log$OffsetIndex$$forceUnmap(OffsetIndex.scala:301)
at kafka.log.OffsetIndex$$anonfun$resize$1.apply(OffsetIndex.scala:283)
at kafka.log.OffsetIndex$$anonfun$resize$1.apply(OffsetIndex.scala:276)
at kafka.utils.Utils$.inLock(Utils.scala:535)
at kafka.log.OffsetIndex.resize(OffsetIndex.scala:276)
at kafka.log.Log.loadSegments(Log.scala:179)
at kafka.log.Log.<init>(Log.scala:67)
at kafka.log.LogManager$$anonfun$loadLogs$2$$anonfun$3$$anonfun$apply$7$$anonfun$apply$1.apply$mcV
at kafka.utils.Utils$$anon$1.run(Utils.scala:54)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
[2015-07-14 17:00:45,219] INFO Completed load of log test-0 with log end offset 0 (kafka.log.Log)
What I observed
When I delete the Kafka log folder, the error does not appear the first time I re-run the starting script. Kafka log folder path:
C:\tmp\kafka-logs
I have tried to stop the service using the provided script, but it does not help. The server stop script:
kafka-server-stop.bat
Although the same error appears when I start it the second time, Kafka start-up continues, and it seems that it works normally.
Help
How to get rid of the above error?

Answer 1

This exception shouldn't be a problem during startup but if you want to get rid of it I guess you have to file a Jira for it.
This seems to be related to KAFKA-1008 and this commit.

Answer 2

/**
* Forcefully free the buffer's mmap. We do this only on windows.
*/
private def forceUnmap(m: MappedByteBuffer) {
try {
if(m.isInstanceOf[sun.nio.ch.DirectBuffer])
(m.asInstanceOf[sun.nio.ch.DirectBuffer]).cleaner().clean()
} catch {
case t: Throwable => warn("Error when freeing index buffer", t)
}
}
when index file size == 0 , cleaner where be null
see
https://github.com/apache/kafka/pull/1718