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From "Matthias J. Sax" <mj...@apache.org>
Subject Re: Flink and Clojure
Date Thu, 10 Dec 2015 16:15:05 GMT
Would it make sense (if possible?) for Flink to add the user jar
dynamically to it's own classpath so Clojure can find it? Or somehow
modify Clojure's class loader?

The jars in lib are added to the classpath at startup. This makes it
practically impossible to execute a Flink program that is written in
Clojure right now...


On 12/10/2015 05:09 PM, Aljoscha Krettek wrote:
> Clojure is not considering the user-jar when trying to load the class.
> 
>> On 10 Dec 2015, at 17:05, Matthias J. Sax <mjsax@apache.org> wrote:
>>
>> Hi Squirrels,
>>
>> I was playing with a Flink Clojure WordCount example today.
>> https://github.com/mjsax/flink-external/tree/master/flink-clojure
>>
>> After building the project with "mvn package" I tried to submit it to a
>> local cluster. Before I started the cluster, I manually copied
>> "clojure-1.5.1.jar" into Flink's lib folder.
>>
>>> cp ~/.m2/repository/org/clojure/clojure/1.5.1/clojure-1.5.1.jar lib/
>>> bin/start-local.sh
>>
>> However, when submitting the jar, I get an exception:
>>
>>> bin/flink run -c org.apache.flink.clojure.WordCount
>> ~/workspace_flink/flink-external/flink-clojure/target/flink-clojure-0.10.0.jar
>>
>>
>>> ------------------------------------------------------------
>>> The program finished with the following exception:
>>>
>>> org.apache.flink.client.program.ProgramInvocationException: The program's entry
point class 'org.apache.flink.clojure.WordCount' threw an error during initialization.
>>> at org.apache.flink.client.program.PackagedProgram.loadMainClass(PackagedProgram.java:585)
>>> at org.apache.flink.client.program.PackagedProgram.<init>(PackagedProgram.java:195)
>>> at org.apache.flink.client.CliFrontend.buildProgram(CliFrontend.java:784)
>>> at org.apache.flink.client.CliFrontend.run(CliFrontend.java:288)
>>> at org.apache.flink.client.CliFrontend.parseParameters(CliFrontend.java:1050)
>>> at org.apache.flink.client.CliFrontend.main(CliFrontend.java:1103)
>>> Caused by: java.lang.ExceptionInInitializerError
>>> at java.lang.Class.forName0(Native Method)
>>> at java.lang.Class.forName(Class.java:278)
>>> at org.apache.flink.client.program.PackagedProgram.loadMainClass(PackagedProgram.java:578)
>>> ... 5 more
>>> Caused by: java.io.FileNotFoundException: Could not locate org/apache/flink/clojure/WordCount__init.class
or org/apache/flink/clojure/WordCount.clj on classpath:
>>> at clojure.lang.RT.load(RT.java:443)
>>> at clojure.lang.RT.load(RT.java:411)
>>> at clojure.core$load$fn__5018.invoke(core.clj:5530)
>>> at clojure.core$load.doInvoke(core.clj:5529)
>>> at clojure.lang.RestFn.invoke(RestFn.java:408)
>>> at clojure.lang.Var.invoke(Var.java:415)
>>> at org.apache.flink.clojure.WordCount.<clinit>(Unknown Source)
>>> ... 8 more
>>
>> I am not sure why the class is not found. It is contained in the jar
>> file. I can fix this error by copying the user jar
>> (flink-clojure-0.10.0.jar) into Flink's lib-folder.
>>
>> It seems, that Flink is not looking into the user-jar when loading this
>> class. Can anybody explain why?
>>
>> Thx.
>>
>> -Matthias
>>
> 


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