Transitive dependency exclusions (Maven vs. Gradle)

Given the following dependency graph, what do you think, which version of guava should be in the classpath?

(our project) ------->  (A)   ------->  (guava 11)
      |   \
      |    ---------->  (B)   ---- exclude guava 27 --->  (C)   ------->  (guava 27)
      \
       -------------->  (D)   ------->  (C)   ------->  (guava 27)    

It turns out, that if we use Maven, then we got guava 11. Maven seems to apply the exclusion of guava 27, even when it gets imported transitively through a path where the exclusion was not defined.

However, when we use Gradle, then we end up with guava 27 on the classpath.

try out for yourself

Prerequisites:

• install maven and gradle
• locally install the 4 dependencies to the maven repo by executing mvn install in the dependency project folders (use sequence A, C, B, D)

Use the following commands to regenerate the dependency trees:

cd maven-test
mvn dependency:tree > ../maven_dependencies.txt
mvn dependency:resolve >> ../maven_dependencies.txt

cd ../gradle-test
gradle dependencies > ../gradle_dependencies.txt