I have a spark job packaged as an uber-jar using the sbt assembly plugin.
The build.sbt specifies a runnable main to be the target of the resulting uber-jar
mainClass in assembly := Some("com.foo.Bar")
After the assembly is correctly created, running the intended command:
java -jar assembly.jar
results in
Error: Could not find or load main class com.foo.Bar
Using the an alternative method, like java -cp assembly.jar com.foo.Bar gives the same error message.
Then, I extracted the contents of the uber-jar in a new directory. I can see my com/foo/ directory and the Bar.class file.
From the root of the extracted directory I tried:
java -cp . com.foo.Bar
and I get a correct result.
Further trying to find the reason of the error, I tried:
java -verbose -jar assembly.jar
I can see the java core classes being loaded, but I don't see any of my packaged classes being loaded.
What can possibly be wrong here?