anchor.diff:      alternatives --install /usr/bin/mvn mvn /usr/local/maven/bin/mvn 100
   
   # install gradle
  -ENV GRADLE_VERSION=2.14.1
  +ENV GRADLE_VERSION=4.2.1
   ENV GRADLE_HOME=/usr/local/gradle
   RUN wget --directory-prefix=/tmp \
       https://services.gradle.org/distributions/gradle-${GRADLE_VERSION}-bin.zip && \
  
positive.code:     yum clean all && rm -rf /var/cache/yum/*
  
  # this envs are for maintaining java updates.
  ENV JAVA_MAJOR_VERSION=8
  ENV JAVA_UPDATE_VERSION=102
  ENV JAVA_BUILD_NUMER=14
  # install java
  ENV JAVA_VERSION=1.${JAVA_MAJOR_VERSION}.0_${JAVA_UPDATE_VERSION}
  ENV JAVA_TARBALL=jdk-${JAVA_MAJOR_VERSION}u${JAVA_UPDATE_VERSION}-linux-x64.tar.gz
  ENV JAVA_HOME=/opt/java/jdk${JAVA_VERSION}
  
  RUN wget --directory-prefix=/tmp \
           --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" \
           http://download.oracle.com/otn-pub/java/jdk/${JAVA_MAJOR_VERSION}u${JAVA_UPDATE_VERSION}-b${JAVA_BUILD_NUMER}/${JAVA_TARBALL} && \
      mkdir -p /opt/java && \
      tar -xzf /tmp/${JAVA_TARBALL} -C /opt/java/ && \
      alternatives --remove java ${SWARM_JAVA_HOME}/bin/java && \
  
negative.code:     rm -rf /tmp/* && rm -rf /var/log/*
  
  # install maven
  ENV MAVEN_VERSION=3.5.0
  ENV M2_HOME=/usr/local/maven
  RUN wget --directory-prefix=/tmp \
      http://mirror.synyx.de/apache/maven/maven-3/${MAVEN_VERSION}/binaries/apache-maven-${MAVEN_VERSION}-bin.tar.gz && \
  