Thanks for the quick reply looks like Chesnay Schepler already found the ticket
https://issues.apache.org/jira/browse/FLINK-3138 <https://issues.apache.org/jira/browse/FLINK-3138> with status: Of course if it would be great if this can be fixed soon, but this can be a bit more obvious somewhere. Thanks! Andrew > On 30 Mar 2016, at 12:39, Timo Walther <twal...@apache.org> wrote: > > I will assign this issue to me and fix it soon, if that's ok? > > Regards, > Timo > > > On 30.03.2016 11:30, Stephan Ewen wrote: >> Looks like something we should fix though. Probably just needs a case >> distinction in the TypeExtractor. >> >> @Andrew, can you post the stack trace into the me linked issue? >> >> We'll try to get at it until the next release... >> >> On Wed, Mar 30, 2016 at 10:58 AM, Chesnay Schepler < >> <mailto:ches...@apache.org>ches...@apache.org <mailto:ches...@apache.org>> >> wrote: >> based on https://issues.apache.org/jira/browse/FLINK-3138 >> <https://issues.apache.org/jira/browse/FLINK-3138> this is not supported for >> non-static methods. >> >> >> On 30.03.2016 10:33, Andrew Ge Wu wrote: >>> Hi, >>> >>> This is not very obvious and looks like a bug. >>> >>> I have a lambda expression to get key from objects in stream: >>> >>> This works: >>> stream.keyBy(value -> value.getId()) >>> >>> This does not: >>> stream.keyBy(myClass::getId) >>> >>> Exception: >>> >>> Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1 >>> at >>> org.apache.flink.api.java.typeutils.TypeExtractor.getUnaryOperatorReturnType(TypeExtractor.java:294) >>> at >>> org.apache.flink.api.java.typeutils.TypeExtractor.getKeySelectorTypes(TypeExtractor.java:253) >>> at >>> org.apache.flink.api.java.typeutils.TypeExtractor.getKeySelectorTypes(TypeExtractor.java:246) >>> at >>> org.apache.flink.streaming.api.datastream.KeyedStream.<init>(KeyedStream.java:87) >>> at >>> org.apache.flink.streaming.api.datastream.DataStream.keyBy(DataStream.java:241) >>> >>> >>> Can someone confirm this? or is there a better way to do it? >>> >>> >>> Thanks! >>> >>> >>> Andrew >>> >>> Confidentiality Notice: This e-mail transmission may contain confidential >>> or legally privileged information that is intended only for the individual >>> or entity named in the e-mail address. If you are not the intended >>> recipient, you are hereby notified that any disclosure, copying, >>> distribution, or reliance upon the contents of this e-mail is strictly >>> prohibited and may be unlawful. If you have received this e-mail in error, >>> please notify the sender immediately by return e-mail and delete all copies >>> of this message. >> >> > -- Confidentiality Notice: This e-mail transmission may contain confidential or legally privileged information that is intended only for the individual or entity named in the e-mail address. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or reliance upon the contents of this e-mail is strictly prohibited and may be unlawful. If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete all copies of this message.