Exception in thread “main” java.lang.AssertionError

I had the same issue.
Forcing maven-compiler-plugin to use javac helped me discover actual compilation errors.

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-compiler-plugin</artifactId>
  <configuration>
    <forceJavacCompilerUse>true</forceJavacCompilerUse>
  </configuration>
</plugin>

More details can be found in this Maven Compiler Plugin bug report

Edit: the issue is fixed in maven-compiler-plugin version 3.10.1