Apache Maven

1. Manage version in file pom.xml

pom.xml

<groupId>com.example</groupId>
<artifactId>day01</artifactId>
<version>${DEMO_VERSION}</version>
<name>day01</name>

How to use ?

$export DEMO_VERSION=1.0
$mvn clean package

2. Multi-module (sub-module)

Step to build

1. Create main project (pom)

pom.xml

...
<packaging>pom</packaging>
...

2. Create maven project in main project

+ main_project
  + pom.xml
  + project01
    + pom.xml 
  + project02
    + pom.xml  

Add project01 and project02 to file pom.xml of main project

<modules>
    <module>project01</module>
    <module>project02</module>
</modules>

Edit pom.xml of project01 and project02 :: add the parent project

<parent>
  <artifactId>main-project</artifactId>
  <groupId>com.demo</groupId>
  <version>1.0</version>
</parent>