JMH dependency vs licensing

[Vladimir Sitnikov]

Hi,

Apache Calcite has `ubenchmark` Maven module for benchmarking purposes, and
it depends on org.openjdk.jmh:jmh-core library for that.
It turns out jmh-core is GPL licensed (e.g.
https://mvnrepository.com/artifact/org.openjdk.jmh/jmh-core ).

Here's my question: is there a licensing issue there?
Should we remove `ubenchmark` module from Calcite's sources?
If so, where is the place to put it?

Here's a relevant part of Calcite's pom.xml:

      <dependency>
        <groupId>org.openjdk.jmh</groupId>
        <artifactId>jmh-core</artifactId>
        <version>${jmh.version}</version>
      </dependency>

Vladimir