Hi there, I'm trying to consult whether a flink class loader(ParentFirstClassLoader or ChildFirstClassLoader) must be a singleton?
I met a problem with the below error message by using sql-client to submit sql jobs to a standalone session model cluster with Flink 1.13.3. I also tried ParentFirstClassLoader & ChildFirstClassLoader, both of them will meet this problem. Caused by: java.lang.ClassCastException: class org.apache.hudi.common.fs.HoodieWrapperFileSystem cannot be cast to class org.apache.hudi.common.fs.HoodieWrapperFileSystem (org.apache.hudi.common.fs.HoodieWrapperFileSystem is in unnamed module of loader org.apache.flink.runtime.execution.librarycache. FlinkUserCodeClassLoaders$ParentFirstClassLoader @*384d2142*; org.apache.hudi.common.fs.HoodieWrapperFileSystem is in unnamed module of loader org.apache.flink.runtime.execution.librarycache. FlinkUserCodeClassLoaders$ParentFirstClassLoader @*35e21dd1*) >From this documentation, it shows I might have two versions of the class which are different in application code and flink libraries. But in my case, Flink should don't contains HoodieWrapperFileSystem class, and I didn't add the hudi-flink-bundle jar to flink lib folder, instead, i used sql-client.sh embedded -j xxxx/huid-flink-bundle-xxx.jar. So I'm wondering if the root reason is that they are loaded by two classloader instances? And it seems that FlinkUserCodeClassLoaders is a singleton, but ParentFirstClassLoader and ChildFirstClassLoader aren't from flink source code.
