[BUG] Caused by: java.lang.NoClassDefFoundError: scala/Product$class

[HeathKang]

Describe the bug
Flink report error when run app :Caused by: java.lang.NoClassDefFoundError: scala/Product$class. And I get such info when search for this error:your scala version is 2.12.x but you are using libraries compiled in scala version 2.11. I also to check the flink scala version and docker image info show flink scala version is 2.12:

SCALA_VERSION=2.12",
"GPG_KEY=E2C45417BED5C104154F341085BACB5AEFAE3202",
 "FLINK_HOME=/opt/flink",
"FLINK_URL_FILE_PATH=flink/flink-1.9.1/flink-1.9.1-bin-scala_2.12.tgz",
"FLINK_TGZ_URL=https://www.apache.org/dyn/closer.cgi?action=download&filename=flink/flink-1.9.1/flink-1.9.1-bin-scala_2.12.tgz",
"FLINK_ASC_URL=https://www.apache.org/dist/flink/flink-1.9.1/flink-1.9.1-bin-scala_2.12.tgz.asc"

So I rebuild the app with change POM.xml to:

<scala.binary.version>2.12</scala.binary.version>
<scala.version>2.12.1</scala.version>
<PULSAR_FLINK_VERSION>2.4.1</PULSAR_FLINK_VERSION>

But it seems this lib didn't have any scala 2.12 version lib in repo.
So there is any plan to push scala 2.12 version lib to repo?

[sijie]

@HeathKang Thank you for reporting this issue. We will take a look at the issue this week and publish the related scala version as needed.

[yjshen]

Since the repo has moved to java implementation, it is scala-free now. The only reason we still have _2.11 or _2.12 is that flink have different scala-versioned modules. You could build a 2.12 compatible version by simply changing scala.binary.version in pom.xml.