Importing pom in dependency management - java

Reading from the doc ,
Do not attempt to import a pom that is defined in a submodule of the current pom. Attempting to do that will result in the build
failing since it won't be able to locate the pom.
Never declare the pom importing a pom as the parent (or grandparent, etc) of the target pom. There is no way to resolve the
circularity and an exception will be thrown.
When referring to artifacts whose poms have transitive dependencies the project will need to specify versions of those artifacts as
managed dependencies. Not doing so will result in a build failure
since the artifact may not have a version specified. (This should be
considered a best practice in any case as it keeps the versions of
artifacts from changing from one build to the next).
I have the following doubt:
a) What does point 3 mean ?
b) In 1st point , why would maven not able to find the sub module pom ? Is not submodule build before the parent ?
In point 3 , I need more clarity on ...When referring to artifacts whose poms have transitive dependencies the project will need to specify versions of those artifacts as managed dependencies....
So, let us say we have project A which we will be imported in our project B <dependencyManagement> section . Now the people who created project A have to mention versions of all transitive dependencies (not direct) of project A in its <dependencyManagement> section ? How can anybody know those versions for all transitive dependencies of project A ?
I got another doubt with point 1. I created basically an skeletal project with a super module and sub module with basically no java code. I will hence share their poms. We will see that build gets successful while this should not be the case according to point 1.
The project structure is as follows :
The pom of super module is as follows :
<?xml version="1.0" encoding="UTF-8"?>
<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.home</groupId>
<artifactId>my-project</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<name>my-project</name>
<url>http://www.example.com</url>
<modules>
<module>./sub-module1/pom.xml</module>
</modules>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.home</groupId>
<artifactId>sub-module1</artifactId>
<version>1.0-SNAPSHOT</version>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<licenses>
<license>
<name>The Apache Software License, Version 2.0</name>
<url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
<distribution>repo</distribution>
</license>
</licenses>
<build>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
<!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
<plugin>
<artifactId>maven-site-plugin</artifactId>
<version>3.7.1</version>
</plugin>
<plugin>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>3.0.0</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
The pom for sub module is as follows :
<?xml version="1.0" encoding="UTF-8"?>
<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.home</groupId>
<artifactId>sub-module1</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
</dependencies>
</project>
When I do mvn clean compile , it builds fine.
Also, I see that even if sub module pom packaging type be kept as jar, scope import does not throw error. It still compiles fine.
For future readers I will summarize the answer. Both points 1 and 2 holds true but it will give error only when POM1 (parent or super module) imports POM2 (sub module or child module) and then POM2 needs POM1 for resolution of dependencies.
In point 1 , this won't be found. In point 2 , it will be found due to inheritance but will create a cycle.
Below I give example so that people can verify.
Super module POM
<?xml version="1.0" encoding="UTF-8"?>
<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.home</groupId>
<artifactId>my-project</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<name>my-project</name>
<url>http://www.example.com</url>
<modules>
<module>./sub-module1/pom.xml</module>
</modules>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.home</groupId>
<artifactId>sub-module1</artifactId>
<version>1.0-SNAPSHOT</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.jsoup</groupId>
<artifactId>jsoup</artifactId>
<version>1.8.3</version>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
</dependencies>
<licenses>
<license>
<name>The Apache Software License, Version 2.0</name>
<url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
<distribution>repo</distribution>
</license>
</licenses>
<build>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
<!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
<plugin>
<artifactId>maven-site-plugin</artifactId>
<version>3.7.1</version>
</plugin>
<plugin>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>3.0.0</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
Sub Module POM
<?xml version="1.0" encoding="UTF-8"?>
<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.home</groupId>
<artifactId>sub-module1</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
<dependency>
<groupId>org.jsoup</groupId>
<artifactId>jsoup</artifactId>
</dependency>
</dependencies>
</project>


b) In 1st point , why would maven not able to find the sub module pom ? Is not submodule build before the parent ?
The submodule is not installed/deployed in a GAV referential (your maven cache or a remote Nexus repo)
That means any project which would reference a submodule pom would not find said pom in a submodule GAV, since what was built, installed and deployed was the main project GAV.
As khmarbaise adds in the comments:
You should never do a <scope>import</scope> inside a project which is already defined as a submodule which means is listed one <module>..</module> entry. Because the resolution of the import scope will be done before the rest which will result in a fail of the build.
And:
a) What does point 3 mean ?
It means the <dependencies> section should declare some <dependency> with only <group> and <artifact>, not <version>.
The version will be fetched from the imported <dependencyManagement>.
See also "Tracking managed dependency versions in Maven".
As illustrated here, managed dependency is used to lock the version at the parent pom.

Related

org.json.* is not accessible in JAVA Maven Project as a dependency

I am making a JavaFX project (for the GUI) on Maven and for the moment I want to convert a StringBuffer object to JSON.
I tried to add the dependency org.json from Maven but there is a problem in pom.xml file
Missing Artifact org.json:json:bundle:20220924
I tried adding an older version of org.json dependency, it had the same issue
I tried a different dependency, everything was ok in the pom.xml file but I could not import it into my project (any dependency).
All dependencies return this error: The type org.json.JSONArray is not accessible
Lastly, I tried to download the json-java.jar from github and add it into a libs folder on the base project directory and added it in the pom file as a dependency but it could not be resolved either.
My pom.xml file:
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>books</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20220924</version>
<type>bundle</type>
</dependency>
<dependency>
<groupId>org.openjfx</groupId>
<artifactId>javafx-controls</artifactId>
<version>13</version>
</dependency>
<dependency>
<groupId>org.openjfx</groupId>
<artifactId>javafx-fxml</artifactId>
<version>13</version>
</dependency>
<dependency>
<groupId>com.sample</groupId>
<artifactId>sample</artifactId>
<version>1.0</version>
<scope>system</scope>
<systemPath>${project.basedir}/libs/json-20220924.jar</systemPath>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
<configuration>
<release>11</release>
</configuration>
</plugin>
<plugin>
<groupId>org.openjfx</groupId>
<artifactId>javafx-maven-plugin</artifactId>
<version>0.0.6</version>
<executions>
<execution>
<!-- Default configuration for running -->
<!-- Usage: mvn clean javafx:run -->
<id>default-cli</id>
<configuration>
<mainClass>com.example.App</mainClass>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
In the end I downloaded Maven again and extracted it into a folder and changed my environment variables on path. Maven is successfully installed on version 3.8.7
Thank you in advance for any help!
UPDATE
I should mention that I tried it on a new java project (without maven) and it works fine, by importing the .jar file from git-hub repository

Vaadin 14 training "RouterAPI" is probably outdatedt, so mvn jetty:run raises an error. How do I need to change the POM file?

as stated I have trouble running mvn jetty:run with the existing vaadin exercise for routing in vs code. As the tutorial was already created under vaadin 10 the pom file is probably outdated, as the other trainigs worked perfectly fine with the mvn jetty:run command.
The exact error is:
No plugin found for prefix 'jetty' in the current project and in the plugin groups [org.apache.maven.plugins, org.codehaus.mojo] available from the repositories [local (C:\Users\Dukatz\.m2\repository), central (https://repo.maven.apache.org/maven2)]
Sadly I'm pretty new do web application development, so I don't have the slightest idea, how to make it work. Hopefully you can help me.
The Tutorial: Vaadin Router Api Tutorial
the POM file:
<?xml version="1.0" encoding="UTF-8"?>
<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.vaadin.trainings.routing</groupId>
<artifactId>exercises-routing</artifactId>
<name>Routing Exercises</name>
<version>1.0.0</version>
<packaging>war</packaging>
<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<failOnMissingWebXml>false</failOnMissingWebXml>
<!-- Dependencies -->
<vaadin.version>13.0.5</vaadin.version>
<servlet.api.version>3.1.0</servlet.api.version>
<!-- Plugins -->
<jetty.version>9.4.15.v20190215</jetty.version>
<maven.war.plugin.version>3.1.0</maven.war.plugin.version>
</properties>
<repositories>
<repository>
<id>vaadin-prereleases</id>
<name>Vaadin Pre-releases</name>
<url>https://maven.vaadin.com/vaadin-prereleases</url>
</repository>
</repositories>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-bom</artifactId>
<type>pom</type>
<scope>import</scope>
<version>${vaadin.version}</version>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<!-- Added to provide logging output as Flow uses -->
<!-- the unbound SLF4J no-operation (NOP) logger implementation -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
</dependency>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-core</artifactId>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>${servlet.api.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>${maven.war.plugin.version}</version>
<configuration>
<archive>
<manifestEntries>
<Implementation-Title>${project.name}</Implementation-Title>
<Implementation-Version>${project.version}</Implementation-Version>
</manifestEntries>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>${jetty.version}</version>
</plugin>
</plugins>
</build>
</project>

There is no Problem with the pom file. Because it's an older lesson, there was no pom file created for the whole project, but only in the specific paths (like \exercises or \solutions). So running mvn jetty:run couldn't work. There was no pom in the directory. I started it in VS-Code with the Maven-Explorer jetty plugin but
mvn jetty:run -f "c:\Users\Dukatz\Desktop\VadinTutorials\Vaadin14-RouterAPI\Exercises\pom.xml"
would do the job from the command line.
Thanks me! I won't delete the question because, one day there's maybe someone as dumb as me.

Spring boot maven build not including artifact version in final jar

On building my spring boot app using mvn clean package, the final artifact that is getting built, myapp.jar, is not having the version number included in the jar name.
What change should i do to get the artifact verion number to be part of jar.
The relevant part of pom.xml is as below -
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.mycomp</groupId>
<artifactId>myapp</artifactId>
<version>2.6.0</version>
<name>myapp</name>
<description>
<![CDATA[]]>
</description>
<packaging>jar</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<springboot.version>2.5.6</springboot.version>
</properties>
<dependencies>
<!-- Spring boot -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>${springboot.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>5.3.12</version>
</dependency>
...
<dependency>
<groupId>org.apache.maven</groupId>
<artifactId>maven-artifact</artifactId>
<version>3.6.3</version>
</dependency>
</dependencies>
<build>
<finalName>gitlab-finder</finalName>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.1.2</version>
</plugin>
</plugins>
</pluginManagement>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${springboot.version}</version>
</plugin>
</plugins>
</build>
</project>
Note: I created a new spring boot project using spring starter (through sts), and for this new project the jar has artifact version included in the jar name by default. So wondering if this a default feature why is this not the case for my project (by the way, i am maintainer of this project not the creator but i have to add this feature of including version number to jar name.)

You are overwriting the default behaviour of generating project names. This is because you define the finalName tag.
From the docs:
finalName: This is the name of the bundled project when it is finally built (sans the file extension, for example: my-project-1.0.jar). It defaults to ${artifactId}-${version}.
In your case it is defined as <finalName>gitlab-finder</finalName> which does not contain the version of the project. You either add ${version} to it <finalName>gitlab-finder-${version}</finalName> or remove the finalName tag.

NoClassDefFoundError: javax/json/bind/JsonbBuilder even after adding javaee-api to dependencies

I am using maven with netbeans. Whenever I run the program it gives me java.lang.NoClassDefFoundError exception even after adding javaee-api 8.0 to dependencies.
Here is my pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<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>example</groupId>
<artifactId>JavaApp</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.5.1</version>
<configuration>
<debug>false</debug>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>12</maven.compiler.source>
<maven.compiler.target>12</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>8.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
</project>
I can see the javax.json.bind.* in Dependencies. I don't get why am I not able to run the program. Any pointers?

The problem you face is that you need to add libraries which you use in your project manually. As you said javaee-api has dependency to javax.json.bind.* but the scope of that is provided which means that it will provide by your jdk or a container (application server for example) in the runtime( for more information about scopes check this). So you need to add libraries you need as compile scope(the default scope) which you need them in runtime.

Supporting android library projects with maven

I am writing an android library project and would like to add the support for maven. My library project pom file looks like this:
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>my_group_id</groupId>
<artifactId>my_artifactId</artifactId>
<version>1.0.1</version>
<packaging>apklib</packaging>
<name>My Library Project</name>
<dependencies>
<dependency>
<groupId>com.google.android</groupId>
<artifactId>android</artifactId>
<version>4.1.1.4</version>
<scope>provided</scope>
</dependency>
</dependencies>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<sourceDirectory>src</sourceDirectory>
<finalName>${project.artifactId}</finalName>
<plugins>
<plugin>
<groupId>com.jayway.maven.plugins.android.generation2</groupId>
<artifactId>android-maven-plugin</artifactId>
<version>3.8.2</version>
<extensions>true</extensions>
<configuration>
<sdk>
<platform>19</platform>
</sdk>
</configuration>
</plugin>
</plugins>
</build>
</project>
My main project pom file looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.simpligility.android</groupId>
<artifactId>helloflashlight</artifactId>
<version>1.0.0</version>
<packaging>apk</packaging>
<name>HelloFlashlight</name>
<dependencies>
<dependency>
<groupId>com.google.android</groupId>
<artifactId>android</artifactId>
<version>4.1.1.4</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>my_group_id</groupId>
<artifactId>my_artifactId</artifactId>
<version>1.0.1</version>
<type>apklib</type>
</dependency>
</dependencies>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<sourceDirectory>src</sourceDirectory>
<finalName>${project.artifactId}</finalName>
<plugins>
<plugin>
<groupId>com.jayway.maven.plugins.android.generation2</groupId>
<artifactId>android-maven-plugin</artifactId>
<version>3.8.2</version>
<extensions>true</extensions>
<configuration>
<sdk>
<platform>19</platform>
</sdk>
</configuration>
</plugin>
</plugins>
</build>
</project>
I am installing the library project to my local repository using:
mvn clean install
then I am compiling and installing the main project to my local repository using:
mvn clean install
and generating the apk using:
mvn android:deploy
Now the problem occurs when I compile the project with maven. The project compiles successfully, however when I am running the apk on the device I receive NullPointerException when trying to perform findById for resources that are inside the library project. Please note that part of the time findById does return value, but not always the correct type (e.g, expected layout but got a button). It is important to say that when running in eclipse without maven everything works perfectly.
Please advise

Finally I found the solution, so I'll update my answer for future readers.
The solution to this problem was to create aar file instead of apklib file using maven.

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