Building a "Maven project" in a Docker container fails with a "connection refused" error message whereas the same build is successful in a "Freestyle project" (also build in a Docker container plugin).

[ael.validate-in-docker-mvnproject] $ docker exec --tty --user 500: dc69be1aed975dbff977348d060329d75d1377ecbefaf929a269a11fc5e40373 env ANT_HOME=/opt/apache-ant-1.8.2 CLASSPATH= EXECUTOR_NUMBER=0 JAVA_HOME=/opt/jdk1.7.0_45 JENKINS_HOME=/data/EDT/jenkins M2_HOME=/opt/apache-maven-3.0.4 MAVEN_HOME=/opt/apache-maven-3.0.4 "MAVEN_OPTS=-Xms1g -Xmx1g -XX:MaxPermSize=256m -Dfile.encoding=Cp1252" no_proxy=/var/run/docker.sock ORACLE_HOME=/opt/oracle11/product/11.2.0/client/ PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/jdk1.7.0_45/bin:/opt/apache-ant-1.8.2/bin:/opt/apache-maven-3.0.4/bin TERM=xterm WORKSPACE=/data/EDT/jenkinsSlave_recette_1/c3f621fe/workspace/ael.validate-in-docker-mvnproject java -cp /data/EDT/jenkinsSlave_recette_1/c3f621fe/maven3-agent.jar:/opt/apache-maven-3.0.4/boot/plexus-classworlds-2.4.jar org.jvnet.hudson.maven3.agent.Maven3Main /opt/apache-maven-3.0.4 /data/EDT/jenkinsSlave_recette_1/slave.jar /data/EDT/jenkinsSlave_recette_1/c3f621fe/maven3-interceptor.jar /data/EDT/jenkinsSlave_recette_1/c3f621fe/maven3-interceptor-commons.jar 44848
Exception in thread "main" java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at java.net.Socket.connect(Socket.java:528)
at java.net.Socket.<init>(Socket.java:425)
at java.net.Socket.<init>(Socket.java:208)
at org.jvnet.hudson.maven3.agent.Maven3Main.main(Maven3Main.java:136)
at org.jvnet.hudson.maven3.agent.Maven3Main.main(Maven3Main.java:70)
Stopping Docker container after build completion