The document discusses Maven, an open source build automation tool used primarily for Java projects. It provides an overview of Maven's key features like dependency management, build lifecycles, and the project object model (POM). The presentation also demonstrates how to create a basic Maven project, configure dependencies and repositories, and manage multi-module builds.

1. Intelligent Projects with
Maven
We’ll examine Maven framework with its architecture and
create some sample projects!
Dev Fest Istanbul
December 2014
Mert ÇALIŞKAN
@mertcal

2. Mert ÇALIŞKAN
• ’02 Hacettepe Graduate
• Lecturer @ Hacettepe
• 10+ Years of Enterprise Java Experience
• Coder @ t2.com.tr
• Author
• Open Source Software Advocate
• Founder of Ankara JUG
• Linkedin Profile available @
bit.ly/mertcaliskan

3. My Books
Details available at http://amazon.com/author/mert

4. How many of you heard
about Maven?
Or using it?

5. Maven is…
• A project management framework from ASF.
• It’s a Uniform Build System.
• Making the build as easy as possible.
• Comprehensive model for software projects.

6. And Maven also is…

7. What Maven provides
• Convention over Configuration
(konfigurasyon yerine kurallar)
• Common Interfaces
The time of build engineers is over
Stop building the build and focus on development !
• Dependency Management
Public repositories
• Plugin Architecture
• Documentation
Generate documentation, reports ...

8. Installing Maven
• You need JDK (not the JRE).
• Just download the binary from
http://maven.apache.org/download.cgi.
• Current latest version is 3.2.3.
• Open it up to a folder and add it to the path of the
OS / Environment Variable.

9. To understand Maven
one first need to
understand
the
Project Object Model
(POM)

10. POM
• It is what makes your project a Maven Project.
• It’s an XML file.
• Not just for building the project; but also,
project’s relationship, list of team members,
license, SCM and etc.
• Not only for Java projects
• you can build FLEX code with appropriate
plugins
• you can build Microsoft binaries from C# code

11. Anatomy of POM
<project ...>
<parent />
<groupId /> <artifactId /> <version />
<packaging />
<developers /> <contributors />
<scm>... </scm>
<build>
<plugins>....</plugins>
</build>
<dependencies>....</dependencies>
<repositories>....</repositories>
<pluginRepositories>... </pluginRepositories>
<profiles>...</profiles>
<reporting>... </reporting>
</project>

12. Simplest POM
<project>
<modelVersion>4.0.0</modelVersion>
<groupId>com.devfesttr</groupId>
<artifactId>MavenApp</artifactId>
<version>1.0.0</version>
</project>
$ mvn install
}
compile code
run tests
package as jar
deploy to local repo

13. Simplest POM
• GAV (groupid - artifactid - version) is the unique
identifier for the project.
• They are also called as the coordinates.
• groupid: is the identifier for a collection of related
modules. It’s more like a hierarchy that starts with the
organization and then move on with the specific
project group. (com.devfesttr)
• artifactid: is the unique identifier or the simple name
of the module within a group (MavenApp)
• version: identifier for the build number of the project.

14. Question here is
How is that possible with 6 lines
of XML?
Where do I define the source
folders, test folders and all other
stuff ?

15. Super POM
• Same analogy with java.lang.Object
• usr/share/Java/maven/lib/maven-model-builder-
3.2.3.jar:org/apache/maven/model/
pom-4.0.0.xml
• Standard directory layout
• Repo def. for http://repo1.maven.org/maven2
• To see the merged POM:
mvn help:effective-pom

16. Let’s create a
Maven Project
• We’ll be using Eclipse Kepler
• IDE for version JavaEE Developers is shipping with
Maven Plugins.
• We’ll also create a project with the archetype soon.

17. Build LifeCycle
• Process for building and distributing an
artefact is clearly defined.
• 3 built-in Life Cycles
default: handles project deployment
clean: clean project files generated by a build
site: generate project’s site doc.
• Each lifecycle consists of phases in specific order.
• Zero or more goals attached to each phase.

18. Build LifeCycle
default
integration-test
validate
compile
test
verify
install
deploy

19. default
mvn integration -test
validate
compile
test
integration-test
verify
install
deploy
mvn phase
mvn phase:goal
mvn phase phase:goal
mvn phase:goal phase:goal
validate
compile
test
integration-test

20. Build LifeCycle
• validate - validate the project is correct and all
necessary information is available
• compile - compile the source code of the project
• test - test the compiled source code using a suitable
unit testing framework. These tests should not
require the code be packaged or deployed
• package - take the compiled code and package it in its
distributable format, such as a JAR.

21. Build LifeCycle
• integration-test - process and deploy the package if
necessary into an environment where integration
tests can be run
• verify - run any checks to verify the package is valid
and meets quality criteria
• install - install the package into the local repository,
for use as a dependency in other projects locally
• deploy - done in an integration or release
environment, copies the final package to the remote
repository for sharing with other developers and
projects.

22. default - full bundle (21 steps)
validate
Validates whether project is correct and all necessary information
is available to complete the build process.
initialize Initialises build state, for example set properties.
generate-sources Generate any source code to be included in compilation phase.
process-sources Process the source code, for example, filter any value.
generate-resources Generate resources to be included in the package.
process-resources
Copy and process the resources into the destination directory,
ready for packaging phase.
compile Compile the source code of the project.
process-classes
Post-process the generated files from compilation, for example to
do bytecode enhancement/optimization on Java classes.
generate-test-sources
Generate any test source code to be included in compilation
phase.
process-test-sources
Process the test source code, for example, filter any values.
test-compile Compile the test source code into the test destination directory.
process-test-classes
Process the generated files from test code file compilation.

23. default - cont’d
test Run tests using a suitable unit testing framework.
prepare-package
Perform any operations necessary to prepare a package before
the actual packaging.
package
Take the compiled code and package it in its distributable format,
such as a JAR, WAR, or EAR file.
pre-integration-test
Perform actions required before integration tests are executed.
For example, setting up the required environment.
integration-test
Process and deploy the package if necessary into an
environment where integration tests can be run.
post-integration-test
Perform actions required after integration tests have been
executed. For example, cleaning up the environment.
verify
Run any check-ups to verify the package is valid and meets
quality criterias.
install
Install the package into the local repository, which can be used
as a dependency in other projects locally.
deploy
Copies the final package to the remote repository for sharing
with other developers and projects.

24. Dependency Mechanism
• It’s where Maven can ease the development when
you have hundreds of modules.
• You may also depend on external frameworks and
maven will fetch them from repositories.
• It happens with the Coordinates ! (GAV factor)
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.7</version>
<scope>compile</scope>
<optional>false</optional>
</dependency>

25. Transitive Dependencies
• Transitive Dependencies are introduced with
Maven version 2.0.
• It allows you get the libraries that your own
dependencies require and include them
automatically. You don’t need to take care of those
explicitly.
• There is no limit to the number of levels on
dependencies.

26. Dependency Exclusion
• If projectX depends on
projectY and
projectY depends on projectZ,
the owner of projectX can
define an exclusion on projectZ
for not to fetch it while fetching
projectY.
X
Y
Z

27. Usage of <exclusion>
<dependency>
<groupId>mycompany</groupId>
<artifactId>myproject</artifactId>
<version>1.0</version>
<exclusions>
<exclusion>
<groupId>mycompany</groupId>
<artifactId>myotherproject</artifactId>
</exclusion>
</exclusions>
</dependency>

28. Optional Dependencies
• Let’s say projectY releases itself
and mark its dependency on
projectZ as optional. When
projectX depends on the
projectY, project X will only
depend on the Y but not the Z.
But it may also add the Z as a
dependency if needed.
X
Y
Z
(optional)

29. Usage of <optional>
• ProjectY defines ProjectZ as below with optional
dep.
<dependency>
<groupId>mycompany</groupId>
<artifactId>projectZ</artifactId>
<version>1.0</version>
<optional>true</optional>
</dependency>

30. Sample <dependencies>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.3.2.Final</version>
</dependency>
</dependencies>

31. Scope for Dependencies
compile
provided
runtime test
system import
CCompile T Classpaths
Test R
Runtime

32. Scope for Dependencies
compile default scope, compile scoped CTR dependencies will be in classpath
provided similar to the compile, artefact should be provided by
JDK / container @ runtime CT
TR runtime not needed for compilation but need @ runtime
T test dependency only needed for test compilation & execution
CT system same as provided, but artefact should be provided
with maven 2.0.9...dependency to be replaced with
the dependencies in that POM's
<dependencyManagement> section.
--- import
explicitly with <systemPath />
Classpath

33. Versioning and Ranges
<major>.<minor>.<incremental> - <qualifier>
1.2.3 / 1.2.3-alpha-01
Be careful with string comparison, ordering at the qualifiers...
1.2.3-alpha-2 > 1.2.3-alpha-10
(, ) - Exclusive
[, ] - Inclusive
<version>[3.8 , 4.11)</version>
<version>[3.8]</version>
Dependency <version>[ , 3.8]</version>
Mediation

34. Release and Snapshot
Versioning
• Snapshot versioning: Used by the projects during
development as it implies that the project is still
under development and it may change.
<version>0.0.2-SNAPSHOT</version>
• Release versioning: It’s the versioning that is assumed
never to change. Only to be used for a single state of
the project when it is released then updated to a
next snapshot.
<version>0.0.1</version>

35. Archetypes
• Templates for Maven projects
• Descriptor XML files + Velocity templates
• To create a Maven project:
mvn archetype:generate -DgroupId=com.devfesttr -DartifactId=sampleApp -
Dversion=1.0-SNAPSHOT -DarchetypeGroupId=org.apache.maven.archetypes -
DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.0

36. Let’s create a
Maven Project
with an archetype
• By using an archetype from JBOSS repository
• https://repository.jboss.org/nexus/content/
repositories/releases/archetype-catalog.xml
• We will have Domain classes, Web Pages, in
memory database, REST services and etc.

37. How Maven resolve
versions?

38. A : A : 1.0
C : C : 1.0 B : B : 1.0
B : B : 2.0
commons-logging
commons-logging
1.0.1
commons-logging
commons-logging
1.1.1
commons-logging
commons-logging
1.1.1
D : D : 1.0
commons-logging
commons-logging
1.0.4
Which B will
Maven choose?
B:2.0
the highest one?
G:A: V

39. A : A : 1.0
C : C : 1.0 B : B : 1.0
B : B : 2.0
commons-logging
commons-logging
1.0.1
commons-logging
commons-logging
1.1.1
commons-logging
commons-logging
1.1.1
D : D : 1.0
commons-logging
commons-logging
1.0.4
Maven will choose
the closest one.

40. A : A : 1.0
C : C : 1.0 B : B : 1.0
B : B : 2.0
? commons-logging
commons-logging
1.0.1
?
commons-logging
commons-logging
1.1.1
commons-logging
commons-logging
1.1.1
D : D : 1.0
commons-logging
commons-logging
1.0.4
Which
commons-logging?
?
?

41. The Sequential first at the same distance…
A : A : 1.0
C : C : 1.0 B : B : 1.0
B : B : 2.0
commons-logging
commons-logging
1.0.1
commons-logging
commons-logging
1.1.1
commons-logging
commons-logging
1.1.1
D : D : 1.0
commons-logging
commons-logging
1.0.4

42. The Final Graph…
A : A : 1.0
C : C : 1.0 B : B : 1.0
D : D : 1.0
commons-logging
commons-logging
1.0.4

43. Question:
Project A will work in the end
OR not?
A : A : 1.0
C : C : 1.0 B : B : 1.0
D : D : 1.0
commons-logging
commons-logging
1.0.4

44. Managing
Projects’ Dependencies

45. Inheritance
ParentApp
<<extends>>
ChildApp
<project>
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.devfesttr</groupId>
<artifactId>ParentApp</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<groupId>devfesttr.workshop</groupId>
<artifactId>ChildApp</artifactId>
<version>1.0.0-SNAPSHOT</version>
</project>

46. Aggregation
ProjectA ProjectB ProjectC
<<depends>> <<depends>>
root $ cd ProjectC
projectC $ mvn compile
projectC $ cd ..
root $ cd ProjectB
projectB $ mvn compile
projectB $ cd ..
root $ cd ProjectA
projectA $ mvn compile
} 8 lines !!!

47. Aggregation
modulesapp
ProjectA ProjectB
ProjectC
<<module>>
<<module>>
<<module>>
root $ cd modulesapp
modulesapp $ mvn compile
modulesapp:
<project>
<modelVersion>4.0.0</modelVersion>
<groupId>com.devfesttr</groupId>
<artifactId>modulesapp</artifactId>
<packaging>pom</packaging>
<version>1.0</version>
<name>modulesapp</name>
<modules>
<module>projectA</module>
<module>projectB</module>
<module>projectC</module>
</modules>
</project>

48. Question here is:
With mvn compile
which module will compile
first?
<modules>
<module>projectA</module>
<module>projectB</module>
<module>projectC</module>
</modules>

49. Repositories
• To manage build artefacts and dependencies
• local or remote repositories
• Can store jar, war, ear, ejb, rar ....
• Maven looks to at least 2 repository if none
specified
- local one (under user home)
- http://repo.maven.apache.org/maven2
(defined in uber-pom)
• Release & Snapshot repositories

50. Repositories
<repository>
<id>jboss-repo</id>
<name>The Release JBoss maven repo</name>
<url>http://repository.jboss.org/maven2</url>
<releases>
<enabled>true</enabled>
</releases>
</repository>
<repository>
<id>jboss-snapshot-repo</id>
<name>The Snapshot JBoss maven repo</name>
<url>http://snapshots.jboss.org/maven2</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>

51. Plugins
• Plugin-oriented Architecture
plugin for even compiling the code..
• A maven artefact w/ descriptor (plugin.xml) and one or more MOJOs
• A MOJO is a Maven plain Old Java Object. Each mojo is an executable
goal in Maven, and a plugin is a distribution of one or more related
MOJOs.
• In short, a MOJO is a maven goal, to extend functionality not already
found in Maven.
• Plexus as its IoC. (Guice also introduced with version 3.x)
Why not Spring?
• List of plugins supported by Maven Project.
https://maven.apache.org/plugins

52. Plugin Development
<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>com.devfesttr</groupId>
<artifactId>hello-maven-plugin</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>maven-plugin</packaging>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-plugin-plugin</artifactId>
<version>3.2</version>
<configuration>
<skipErrorNoDescriptorsFound>true</skipErrorNoDescriptorsFound>
</configuration>
<executions>
<execution>
<id>mojo-descriptor</id>
<goals>
<goal>descriptor</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>

53. Plugin Development
<dependencies>
<dependency>
<groupId>org.apache.maven</groupId>
<artifactId>maven-plugin-api</artifactId>
<version>2.0</version>
</dependency>
<dependency>
<groupId>org.apache.maven.plugin-tools</groupId>
<artifactId>maven-plugin-annotations</artifactId>
<version>3.2</version>
</dependency>
</dependencies>
</project>

54. Plugin Development
Mojo Code
import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugins.annotations.Mojo;
@Mojo( name = "sayhi")
public class GreetingMojo extends AbstractMojo {
public void execute() throws MojoExecutionException {
getLog().info( "Hello world." );
}
}

55. Use the plugin
<build>
<plugins>
<plugin>
<groupId>com.devfesttr</groupId>
<artifactId>hello-maven-plugin</artifactId>
<version>1.0-SNAPSHOT</version>
<executions>
<execution>
<phase>compile</phase>
<goals>
<goal>sayhi</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>

56. What we did w/ plugins in
PrimeFaces
• maven-jsf-plugin
• Component Class
• Tag Handler Class
• Declare Component, Tag, Renderer classes in faces-config.xml
• Declare facelet tag definition
• Declare tld tag definition
• plugin available @
http://repository.primefaces.org/org/primefaces/maven-jsf-plugin

57. settings.xml
• Maven provides 2 settings file,
• Local settings.xml at %USER_HOME%/.m2/settings.xml
• Global settings.xml at %M2_HOME%/conf/settings.xml
• These files are not bundled with Maven project and don’t get
distributed.
• If both files exist, their contents get merged.
• Local settings.xml overrides the global one.

58. Thank you..!