DevOps Classroom notes 28/Nov/2024

Java Build Tools

ANT

• This was the tool created by Apache foundation
• This build tool uses a configuration file called as build.xml
• Ant works based on configuration

<?xml version="1.0"?>
<project name="MyAntProject" default="run" basedir=".">
    <property name="src.dir" location="src"/>
    <property name="build.dir" location="bin"/>
    <property name="jar.dir" location="dist"/>

    <target name="clean">
        <delete dir="${build.dir}"/>
        <delete dir="${jar.dir}"/>
    </target>

    <target name="makedir">
        <mkdir dir="${build.dir}"/>
        <mkdir dir="${jar.dir}"/>
    </target>

    <target name="compile" depends="makedir">
        <javac srcdir="${src.dir}" destdir="${build.dir}"/>
    </target>

    <target name="jar" depends="compile">
        <jar destfile="${jar.dir}/MyAntProject.jar" basedir="${build.dir}">
            <manifest>
                <attribute name="Main-Class" value="test.Main"/>
            </manifest>
        </jar>
    </target>

    <target name="run" depends="jar">
        <java jar="${jar.dir}/MyAntProject.jar" fork="true"/>
    </target>
</project>

Maven

• This is an opensource project hosted by apache
• Design goal:
  • Convention over configuration
  • include dependency and release management
  • includes test execution
  • can be configurable
• Maven build tool expects a file called pom.xml (project object model)

- src
  - main
     - java
         - *.java
  - test
     - java
         - *.java

pom.xml

• POM (Project object model)
• Goals:
  • clean: remove target folder
  • verify: (verify the pom and project)
  • compile: compile the java code and create class files in target folder
  • test: run the unit tests and generate xml reports
  • package: creates the package
  • install: copy the package and pom to local repo (~/.m2)
  • deploy: copy the package to remote repo
• Maven will download dependencies in folder ~/.m2/repository
• Installing Maven:
  • download link
• Lets build the spring petclinic using maven with command mvn package which will compile, run the tests and create the package
• in some projects we will see mvnw files these are called as maven wrappers, they install necessary version of maven and execute goal
• Central, Remote and Local Repos in Maven
  

Installing jdk

• JDK comes in different flavors
  • openjdk
  • eclipse temurin
  • amazon correto
  • oracle jdk
• to install openjdk 17 on ubuntu

sudo apt update
sudo apt install openjdk-17-jdk
java -version