FailedConsole Output

Established TCP socket on 54960
<===[JENKINS REMOTING CAPACITY]===>channel started
Executing Maven:  -B -f /home/hudson/genie.geogig/.jenkins/jobs/geogig-master/workspace/src/pom.xml -Dmaven.repo.local=/home/hudson/genie.geogig/.jenkins/jobs/geogig-master/workspace/.repository clean install -Pexperimental -DskipTests=false -Dcucumber.options=--monochrome --plugin json:target/cucumber.json
[INFO] Scanning for projects...
[WARNING] Some problems were encountered while building the effective model for org.locationtech.geogig:geogig-flatbuffers:jar:2.0-SNAPSHOT
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ org.locationtech.geogig:geogig-flatbuffers:[unknown-version], /home/hudson/genie.geogig/.jenkins/jobs/geogig-master/workspace/src/storage/flatbuffers/pom.xml, line 22, column 15
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO] GeoGig Root                                                        [pom]
[INFO] CRS Metadata support                                               [jar]
[INFO] GeoGig Core API                                                    [jar]
[INFO] GeoGig Core                                                        [jar]
[INFO] Replication and synchronization                                    [jar]
[INFO] Storage backends                                                   [pom]
[INFO] Flatbuffers serialization protocol                                 [jar]
[INFO] Rocksdb backed support for temporary storage                       [jar]
[INFO] RevObject cache implementations                                    [pom]
[INFO] Caffeine implementation of SharedCache                             [jar]
[INFO] GeoGig Command Line Interface                                      [pom]
[INFO] GeoGig Command Line Interface Core                                 [jar]
[INFO] geogig-cli-remoting                                                [jar]
[INFO] PostgreSQL Storage Backend                                         [jar]
[INFO] RocksDB storage backend                                            [jar]
[INFO] Guava Cache implementation of SharedCache                          [jar]
[INFO] GeoGig Pull Requests Support Commands                              [jar]
[INFO] GeoTools modules parent                                            [pom]
[INFO] GeoGig to GeoTools Feature model adapter                           [jar]
[INFO] GeoTools Command Extension                                         [jar]
[INFO] GeoGig DataStore Implementation                                    [jar]
[INFO] GeoGig CLI GeoTools                                                [jar]
[INFO] GeoGigi CLI Postgres Storage Commands                              [jar]
[INFO] GeoGig Experimental Modules                                        [pom]
[INFO] GeoGig Query Language Extension                                    [jar]
[INFO] GeoGig CLI App                                                     [jar]
[INFO] -------------------< org.locationtech.geogig:geogig >-------------------
[INFO] Building GeoGig Root 2.0-SNAPSHOT                                 [1/26]
[INFO] --------------------------------[ pom ]---------------------------------
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ geogig ---
[INFO] --- maven-enforcer-plugin:3.0.0-M2:enforce (enforce-maven) @ geogig ---
[WARNING] Rule 0: org.apache.maven.plugins.enforcer.RequireMavenVersion failed with message:
Detected Maven Version: 3.6.0 is not in the allowed range 3.6.1.
[JENKINS] Archiving disabled