❮ Maven Build Profiles Maven Setup ❯

Maven Snapshot (SNAPSHOT)

A large software application typically consists of multiple modules, with the common scenario being multiple teams developing different modules of the same application. For example, imagine a team developing the frontend of the application, with the project named app-ui (app-ui.jar:1.0), and another team developing the backend, using the project data-service (data-service.jar:1.0).

Now, a possible scenario is that the team developing data-service is making rapid bug fixes or project improvements and they are releasing the library to the remote repository almost every other day. If the data-service team uploads a new version every other day, the following issues will arise:

The data-service team must inform the app-ui team each time they release updated code.
The app-ui team needs to frequently update their pom.xml file to the latest version.

To address this situation, the concept of snapshots comes into play.

What is a Snapshot?

A snapshot is a special version that indicates a current copy of the development progress. Unlike regular versions, Maven checks the remote repository for new snapshots each time it builds. Now, the data-service team will release a snapshot of the updated code to the repository each time, such as data-service:1.0-SNAPSHOT, replacing the old snapshot jar.

Project Snapshot vs Version

For versions, if Maven has previously downloaded a specified version file, such as data-service:1.0, Maven will not download a new available 1.0 file from the repository again. To download updated code, the version of data-service needs to be upgraded to 1.1.

In the case of snapshots, each time the app-ui team builds their project, Maven will automatically fetch the latest snapshot (data-service:1.0-SNAPSHOT).

app-ui Project's pom.xml File

The app-ui project uses the 1.0 snapshot of the data-service project.

&lt;project xmlns="http://maven.apache.org/POM/4.0.0" 
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
   http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>app-ui</groupId>
   <artifactId>app-ui</artifactId>
   <version>1.0</version>
   <packaging>jar</packaging>
   <name>health</name>
   <url>http://maven.apache.org</url>
   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>
   <dependencies>
      <dependency>
      <groupId>data-service</groupId>
         <artifactId>data-service</artifactId>
         <version>1.0-SNAPSHOT</version>
         <scope>test</scope>
      </dependency>
   </dependencies>
</project>

data-service Project's pom.xml File

The data-service project releases a 1.0 snapshot for each minor change.

&lt;project xmlns="http://maven.apache.org/POM/4.0.0" 
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
   http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>data-service</groupId>
   <artifactId>data-service</artifactId>
   <version>1.0-SNAPSHOT</version>

<packaging>jar</packaging>
<name>health</name>
<url>http://maven.apache.org</url>
<properties>
   <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
</project>

Although, in the case of snapshots, Maven automatically fetches the latest snapshot in daily work, you can also use the -U parameter in any Maven command to force Maven to download the latest snapshot build.

mvn clean package -U

Let's open the command console, go to the C:\ > MVN > app-ui directory, and execute the following Maven command.

C:\MVN\app-ui>mvn clean package -U

Maven will start building the project after downloading the latest snapshot of data-service.

[INFO] Scanning for projects...
[INFO] -------------------------------------------------------------------
[INFO] Building consumerBanking
[INFO]    task-segment: [clean, package]
[INFO] -------------------------------------------------------------------
[INFO] Downloading data-service:1.0-SNAPSHOT
[INFO] 290K downloaded.
[INFO] [clean:clean {execution: default-clean}]
[INFO] Deleting directory C:\MVN\app-ui\target
[INFO] [resources:resources {execution: default-resources}]
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\app-ui\src\main\
resources
[INFO] [compiler:compile {execution: default-compile}]
[INFO] Compiling 1 source file to C:\MVN\app-ui\target\classes
[INFO] [resources:testResources {execution: default-testResources}]
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\app-ui\src\test\
resources
[INFO] [compiler:testCompile {execution: default-testCompile}]
[INFO] Compiling 1 source file to C:\MVN\app-ui\target\test-classes
[INFO] [surefire:test {execution: default-test}]
[INFO] Surefire report directory: C:\MVN\app-ui\target\
surefire-reports
-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.companyname.bank.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.027 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

[INFO] [jar:jar {execution: default-jar}] [INFO] Building jar: C:\MVN\app-ui\target\ app-ui-1.0-SNAPSHOT.jar [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESSFUL [INFO] ------------------------------------------------------------------------ [INFO] Total time: 2 seconds [INFO] Finished at: Tue Jul 10 16:52:18 IST 2012 [INFO] Final Memory: 16M/89M [INFO] ------------------------------------------------------------------------

❮ Maven Build Profiles Maven Setup ❯