Warning during Maven build

[pkiraly]

I just cloned the repository, and built the application. I get some warning and error messages:

$ mvn clean install
[INFO] Scanning for projects...
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for de.unibonn.iai.eis:luzzu-assessment:jar:2.0.1
[WARNING] 'build.pluginManagement.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-javadoc-plugin @ de.unibonn.iai.eis:luzzu:2.0.1, /home/kiru/git/Luzzu/pom.xml, line 301, column 19
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for de.unibonn.iai.eis:luzzu-semantics:jar:2.0.1
[WARNING] 'build.pluginManagement.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-javadoc-plugin @ de.unibonn.iai.eis:luzzu:2.0.1, /home/kiru/git/Luzzu/pom.xml, line 301, column 19
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for de.unibonn.iai.eis:luzzu-annotations:jar:2.0.1
[WARNING] 'build.pluginManagement.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-javadoc-plugin @ de.unibonn.iai.eis:luzzu:2.0.1, /home/kiru/git/Luzzu/pom.xml, line 301, column 19
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for de.unibonn.iai.eis:luzzu-communications:jar:2.0.1
[WARNING] 'build.pluginManagement.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-javadoc-plugin @ de.unibonn.iai.eis:luzzu:2.0.1, /home/kiru/git/Luzzu/pom.xml, line 301, column 19
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for de.unibonn.iai.eis:luzzu-io:jar:2.0.1
[WARNING] 'build.pluginManagement.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-javadoc-plugin @ de.unibonn.iai.eis:luzzu:2.0.1, /home/kiru/git/Luzzu/pom.xml, line 301, column 19
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for de.unibonn.iai.eis:luzzu-operations:jar:2.0.1
[WARNING] 'build.pluginManagement.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-javadoc-plugin @ de.unibonn.iai.eis:luzzu:2.0.1, /home/kiru/git/Luzzu/pom.xml, line 301, column 19
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for de.unibonn.iai.eis:luzzu-qml:jar:2.0.1
[WARNING] 'build.pluginManagement.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-javadoc-plugin @ de.unibonn.iai.eis:luzzu:2.0.1, /home/kiru/git/Luzzu/pom.xml, line 301, column 19
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for de.unibonn.iai.eis:luzzu-webapp:jar:2.0.1
[WARNING] 'build.pluginManagement.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-javadoc-plugin @ de.unibonn.iai.eis:luzzu:2.0.1, /home/kiru/git/Luzzu/pom.xml, line 301, column 19
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for de.unibonn.iai.eis:luzzu:pom:2.0.1
[WARNING] 'build.pluginManagement.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-javadoc-plugin @ line 301, column 19
[WARNING] 
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING] 
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING] 
...
[INFO] Building Luzzu Semantics Module 2.0.1
...
[INFO] Executing tasks
     [echo] Compiling Vocabularies into Classes
     [echo] daQ
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-log4j12/1.7.5/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-jdk14/1.7.5/slf4j-jdk14-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Schemagen failed to run:
Failed to read input source file:src/main/resources/vocabularies/daq/daq.ttl
Caused by: Not found: file:src/main/resources/vocabularies/daq/daq.ttl
     [java] Java Result: 1
     [echo] void
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-log4j12/1.7.5/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-jdk14/1.7.5/slf4j-jdk14-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Schemagen failed to run:
Failed to read input source file:src/main/resources/vocabularies/void/void.ttl
Caused by: Not found: file:src/main/resources/vocabularies/void/void.ttl
     [java] Java Result: 1
     [echo] qpro
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-log4j12/1.7.5/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-jdk14/1.7.5/slf4j-jdk14-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Schemagen failed to run:
Failed to read input source file:src/main/resources/vocabularies/qpro/qpro.ttl
Caused by: Not found: file:src/main/resources/vocabularies/qpro/qpro.ttl
     [java] Java Result: 1
     [echo] cube
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-log4j12/1.7.5/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-jdk14/1.7.5/slf4j-jdk14-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Schemagen failed to run:
Failed to read input source file:src/main/resources/vocabularies/cube/cube.ttl
Caused by: Not found: file:src/main/resources/vocabularies/cube/cube.ttl
     [java] Java Result: 1
     [echo] sdmx attribute
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-log4j12/1.7.5/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-jdk14/1.7.5/slf4j-jdk14-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Schemagen failed to run:
Failed to read input source file:src/main/resources/vocabularies/cube/sdmx-attribute.ttl
Caused by: Not found: file:src/main/resources/vocabularies/cube/sdmx-attribute.ttl
     [java] Java Result: 1
     [echo] lmi
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-log4j12/1.7.5/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-jdk14/1.7.5/slf4j-jdk14-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Schemagen failed to run:
Failed to read input source file:src/main/resources/vocabularies/lmi/lmi.ttl
Caused by: Not found: file:src/main/resources/vocabularies/lmi/lmi.ttl
     [java] Java Result: 1
     [echo] prov
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-log4j12/1.7.5/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-jdk14/1.7.5/slf4j-jdk14-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Schemagen failed to run:
Failed to read input source file:src/main/resources/vocabularies/prov/prov.ttl
Caused by: Not found: file:src/main/resources/vocabularies/prov/prov.ttl
     [java] Java Result: 1
     [echo] sdmx dimension
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-log4j12/1.7.5/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/[path_to]/.m2/repository/org/slf4j/slf4j-jdk14/1.7.5/slf4j-jdk14-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Schemagen failed to run:
Failed to read input source file:src/main/resources/vocabularies/cube/sdmx-dimension.ttl
Caused by: Not found: file:src/main/resources/vocabularies/cube/sdmx-dimension.ttl
     [java] Java Result: 1
[INFO] Executed tasks

$ java -version

openjdk version "1.8.0_131"
OpenJDK Runtime Environment (build 1.8.0_131-8u131-b11-2ubuntu1.16.04.3-b11)
OpenJDK 64-Bit Server VM (build 25.131-b11, mixed mode)

$ javac -version

javac 1.8.0_131

$ mvn -version

Apache Maven 3.2.1 (ea8b2b07643dbb1b84b6d16e1f08391b666bc1e9; 2014-02-14T18:37:52+01:00)
Maven home: /usr/share/maven3
Java version: 1.8.0_131, vendor: Oracle Corporation
Java home: /usr/lib/jvm/java-8-openjdk-amd64/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "4.4.0-83-generic", arch: "amd64", family: "unix"