The file should be at http://repo2.maven.org/maven2/org/mongodb/mongo-java-driver/maven-metadata.xml and needs to list the available version of the artifact.

See http://repo2.maven.org/maven2/org/slf4j/slf4j-api/maven-metadata.xml for an example.

Without this file, Maven cannot resolve version ranges like '[2,3)' for the mongo-java-driver artifact (or even simple ranges like [2.4], which are useful for enforcing a consistent version of a dependency across a number of components).

The org.mongodb:bson artifact is missing maven-metadata.xml as well.