DevOps Classroomnotes 11/May/2022

Building Java Code with Maven

  • Maven is a software project management tool (build, dependency management tool)
  • This is based on the concept of project object model (POM)
  • Maven provides
    • build
    • test
    • reports
    • documentation
    • releases
  • Maven follows convention over configuration
Item Default
source code ${basedir}/src/main/java
Resources ${basedir}/src/main/resources
Tests ${basedir}/src/test
Compile byte code ${basedir}/target/classes
distributable (jar/war) ${basedir}/target

Installing Maven

  • Ensure java is installed
sudo apt update
sudo apt install openjdk-11-jdk -y

  • Maven can be downloaded and installed manually Refer Here
  • Now lets use apt
sudo apt install maven -y
mvn --version

* Now lets try to install maven using tar file

cd /tmp
tar -xvzf  apache-maven-3.8.5-bin.tar.gz
sudo mv apache-maven-3.8.5 /opt/
  • set the following environmental variables in /etc/profile.d/
export M2_HOME='/opt/apache-maven-3.8.5'
export PATH
  • Logout & Login
mvn --version


  • The developers will create the pom.xml file, but we need to understand
  • When building the java project,
    • compile the code
    • run the unit tests
    • create a package
  • In Maven we have goals/build phase
    • compile => Creates .class files
    • test => runs the unit tests and generates the reports. This will also try to compile
    • package => creates the jar/war file. This will execute compile + test
    • install
    • deploy
    • clean => remove the target folder
  • Maven dowloads the dependencies by default from internet Refer Here
  • Lets compile the spring petclinic
  • Maven when it downloads the dependencies, uses the folder in ${HOME-DIR}\.m2
  • We can combine goals
mvn clean package
mvn compile test package
  • Exercise: Make the jenkins build any java project using mvn package

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