Develop Reference

How to make a plugin-like architecture runnable?

We have a couple of legacy Java projects, which we converted to Maven projects / modules. Previously, all projects were NetBeans projects and had no real dependency management. External dependencies existed on the companies network drive and were directly included as JARs in the NetBeans projects of each module. For the internal dependencies, simple project references were used. It was a pain to build everything because the programmer had to build everything in the right order.
Now, we are in the position that we can open all the Maven modules in IntelliJ IDEA and NetBeans. However, I am having trouble figuring out the best way to combine the different modules and external dependencies in a specific way, which conforms to in-house plugin-like structure. Especially with NetBeans (developing with both IDEs must be possible).
Here is how the git repositories / project structure roughly looks like. The folder structure of the modules is the default Maven structure for each module. The list feature of this site was too clumsy, so I included it as screenshot...
We have an internal maven repository for the stuff and building with maven etc. is working. For Intellij IDEA i can run and debug the end product for customer1 via a custom run configuration, which copies the needed files in the needed structure:
With IntelliJ IDEA, I can debug the software, but I think that the approach (custom IntelliJ run config I created, pointing to all needed JARs and files directly) is rather ugly, and for NetBeans I could not find a similar "run configuration" mechanism.
So I tried to achieve this build process by creating a new "Customer1Runnable" Maven project as a sort of build description, which points to all needed Maven modules. Based on this, I believed I could achieve and automatism to create the needed software structure. Ergo copy all modules into a plugin folder and all dependencies of the modules into a lib folder inside the Customer1Runnable project, using the maven-assembly-plugin.
First off, is my assumption correct that this is a possible use case for the maven-assembly-plugin?
The project itself does not have any source files, it is only a pom.xml and the assembly-config.xml descriptor. I attached the assembly-plugin to the package phase. When running the mvn package command all connected modules are built, but for the execution of the assembly-plugin I get the following output:
For starters, I only tried to include one module in the assembly descriptor. This is the XML (opicom-assembly.xml) for it:
<assembly xmlns="http://maven.apache.org/ASSEMBLY/2.1.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/ASSEMBLY/2.1.0 http://maven.apache.org/xsd/assembly-2.1.0.xsd">
<id>opicom-assembly</id>
<formats>
<format>dir</format>
</formats>
<includeBaseDirectory>false</includeBaseDirectory>
<moduleSets>
<moduleSet>
<useAllReactorProjects>true</useAllReactorProjects>
<includes>
<include>my.company.reporting:module1</include>
</includes>
</moduleSet>
</moduleSets>
</assembly>
pom.xml of Customer1Runnable project
<?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>
<version>1.6</version>
<groupId>my.company.customer1</groupId>
<artifactId>OpicomRunnable</artifactId>
<packaging>pom</packaging>
<name>OpicomRunnable</name>
<repositories>
<repository>
<id>Company-Maven-Repo</id>
<url>file:\\\\MyCompany\TFSDrop\MavenRepo</url>
</repository>
</repositories>
<modules>
<module>../my.company.customer1.module1</module>
<module>../my.company.customer1.module2</module>
.
.
.
<module>../../MyCompany_Common/Report/my.company.reporting.module1</module>
</modules>
<build>
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.3.0</version>
<inherited>true</inherited>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<descriptors>
<descriptor>opicom-assembly.xml</descriptor>
</descriptors>
</configuration>
</plugin>
</plugins>
</build>
</project>
The pom of a module 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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>my.company</groupId>
<artifactId>reporting</artifactId>
<version>1.3</version>
<relativePath>../pom.xml</relativePath>
</parent>
<artifactId>module1</artifactId>
<version>1.3</version>
<packaging>jar</packaging>
<dependencies>
<!-- external dependencies -->
<dependency>
<groupId>commons-pool</groupId>
<artifactId>commons-pool</artifactId>
<version>1.6</version>
</dependency>
<dependency>
<groupId>com.oracle.database.jdbc</groupId>
<artifactId>ojdbc8</artifactId>
<version>21.1.0.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.3.0</version>
<configuration>
<finalName>my-company-${project.artifactId}</finalName>
<appendAssemblyId>false</appendAssemblyId>
<outputDirectory>../build</outputDirectory>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
</project>
Thanks for any input on what I am doing wrong here / how to achieve this with Maven.
EDIT:
As requested, here an example project as ZIP-File.
https://drive.google.com/drive/folders/1ilJeTrOPgYgUTdOP0J4BQcBnPT5fls0k?usp=sharing
The parent directories ModuleGroupCustomer and ModuleGroupCommon do represent git repositories in the real scenario. The relative module path is caused, because the maven project which should be my "run config" points to maven projects in both repositories.
Maybe I am misunderstanding Maven in general? I thought of it in terms of use cases for dependency management similar to .Net nuget packages, but also as "project configuration" like ordinary NetBeans/Intellij projects.
Is it better to simply stick to the existing NetBeans projects for day to day development?

After a long and tedious process of trial and error, I have found a solution which is working for me. So I decided to share the solution online, in case someone else runs into a similar problem. Here is a link to the final zip archive containing working example projects => File CustomerRunnable_RunningAssemblyPluginStackoverflowExample.zip https://drive.google.com/drive/u/0/folders/1ilJeTrOPgYgUTdOP0J4BQcBnPT5fls0k
My error was that I misunderstood how the assembly-plugin works. The approach that I executed the plugin inside my aggregator pom (CustommerRunnable) is wrong, as this maven project only exists as parent pom.
The CustommerRunnable pom.xml references all customer plugins as modules. Those modules have not the CustommerRunnable as parent, but a different pom. Then I created a separate maven project "distribution". The pom.xml of the distribution defines all the plugins (needed customer maven modules) as dependencies. It also has the CustommerRunnable pom.xml as parent. Hence when I run the project in NetBeans, all connected modules are also build(if necessary).
It also configures the assembly plugin. The assembly plugin is attached to the maven package-phase and thus executed with it. It also uses a custom assembly descriptor, which copies all the previously defined plugins into the right folders. This is done by using dependencySets with include and exclude patterns.
See https://maven.apache.org/plugins/maven-assembly-plugin/advanced-descriptor-topics.html for details on this.
So one dependencySet copies all jar files of all plugins to a /plugin folder by using an include pattern. Then this approach is inversed to copy the jar files of all external dependencies to a /lib folder.
The descriptor also defines some extra files to copy to a particular location. exec-maven-plugin, so I can comfortably start the customer software out of NetBeans. I didn't yet manage to configure the execute plugin correctly regarding the needed classpath arguments.
Endresult looks like this:
It is also worth noting that the configurations of the "Build project", "Run project" and "Debug project" inside NetBeans need a tiny bit of modification. (Right Click Module "distribution" -> "Properties" -> point "Actions"

Maven packaging for websphere

I am trying to build an EAR file - Which can be deployed in IBM websphere server.
This is an existing struts appliation, i am trying to mavenize it.
This project contains two folders
1. web
2. webEAR
web is actually for war file and webEAR folder for the EAR file, web contains all the code, and webEAR is a kind of a wrapper.
Steps I have already done are below
IDE - Eclipse
Java version - 1.7
Convereted both web and webEAR to Maven - (Configure to Maven)
edited the POM.XML like below
<modelVersion>4.0.0</modelVersion>
<groupId>com.comp.web</groupId>
<artifactId>web</artifactId>
<version>0.0.1</version>
<packaging>war</packaging>
<name>WEB</name>
<description>WEB</description>
added all relevant jar files - which are in lib folder as below (sample)
<dependency>
<groupId>jarfile</groupId>
<artifactId>com.ibm.jar</artifactId>
<version>1.0</version>
<scope>system</scope>
<systemPath>${basedir}/WebContent/WEBINF/lib/com.ibm.jarfile.jar</systemPat>
</dependency>
Now i dont have any errors in the eclipse, and I can run the application by right clicking the webEAR folder -> Run in Server, It works.
but I am not sure, how to create a EAR file , which has the war file, so that I can deploy in the WAS server dev environment.
Can someone show me a way I can do this. currently there is no POM.xml in the webEAR maven folder
P.S - I am not a Java developer. This is a first maven related project I am assigned to. I appreciate any help

Your module should have <packaging>ear</packaging>.
In the dependencies for this ear module ( Use a new module to build the ear ) include your war module as below.
<dependency>
<groupId>com.comp.webGroupId</groupId>
<artifactId>war-artifact</artifactId>
<version> war-version</version>
<type>war</type>
</dependency>
In the build plugins for this ear module include the maven-ear-plugin.
<plugin>
<artifactId>maven-ear-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<finalName>web</finalName>
<version>versionNumber</version>
<generatedDescriptorLocation>${basedir}/src/main/application/META-INF</generatedDescriptorLocation>
<modules>
<webModule>
<groupId>com.comp.webGroupId</groupId>
<artifactId>war-artifact</artifactId>
<uri>web.war</uri>
<bundleFileName>web.war</bundleFileName>
<contextRoot>/applicationName</contextRoot>
</webModule>
</modules>
</configuration>
</plugin>
Add any specific configuration values as required.

Best way to build twice the same webapp with different dependencies using maven

I have a maven project with a webapp for which I need two versions, each one having its own set of dependencies. The intent is to support two different (and conflicting) versions of a storage client. The webapp code, configuration file and anything but certain libraries is the same in both cases. The right client is loaded at runtime : I just need to drop the right jar (and its dependencies) in the lib folder of the webapp.
If I deploy the dependencies manually, I lose the opportunity to check for version conflicts (which I do when I build a maven project with all its dependencies correctly set).
I do not want to deploy the webapp(s) on the maven repository since it is not a library and it only makes a big archive (mainly because of the embedded dependencies) that consumes space for nothing. Thus, to build the final wars, I cannot add a dependency on the webapp project.
I do not want to duplicate the common webapp class files and configuration files in two different modules. It would make future evolutions more difficult because of the necessary synchronization between the two modules each time one file is updated.
Any suggestion on how to solve this ?
Note that the best solution should allow to build both wars at once.

Use Maven profiles.
http://maven.apache.org/guides/introduction/introduction-to-profiles.html
You can put certain dependencies into certain profiles and activate/deactivate them through the command line with the -P parameter.

I guess defining two profiles in your pom might do the trick :
<project [...]>
[...]
<profiles>
<profile>
<id>storage1</id>
<dependencies>
<dependency>
<groupId>my.group.storage</groupId>
<artifactId>thisOne</artifactId>
<version>13</version>
</dependency>
</dependencies>
</profile>
<profile>
<id>storage2</id>
<dependencies>
<dependency>
<groupId>my.group.storage</groupId>
<artifactId>thisOtherOne</artifactId>
<version>37</version>
</dependency>
</dependencies>
</profile>
</profiles>
[...]
</project>
Call one or the other with mvn -P storage1 or mvn -P storage2. You can also make one active by default, use activation triggers based on other properties, etc.
Here's their introduction article.

In the end, I did not use profiles. There was an issue building both webapp versions at once.
Instead I used war overlays https://maven.apache.org/plugins/maven-war-plugin/overlays.html.
First, I created a skinny war version of the webapp. The skinny war does not include libraries nor META-INF files. Only resources like configuration files. The webapp classes are packaged in a jar (using the attachedClasses configuration option of the maven-war-plugin). I do not mind having this war deployed since it is very lightweigth. Here is the configuration of the maven-war-plugin :
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<configuration>
<outputFileNameMapping>#{groupId}#.#{artifactId}#-#{version}##{dashClassifier?}#.#{extension}#</outputFileNameMapping>
<attachClasses>true</attachClasses>
<archive>
<addMavenDescriptor>false</addMavenDescriptor>
</archive>
<packagingExcludes>WEB-INF/classes/**/*,WEB-INF/lib/*</packagingExcludes>
</configuration>
</plugin>
Then, I created 2 additional modules, one for each flavour of the webapp. In the dependencies, I set :
- the webapp as a dependency of type war
- the jar of the webapp classes
- the storage client library
That way, maven checks for dependency conflicts in all the libraries. The webapp classes are imported through the dependency. The overlay war is used to build the final war. No duplicate code between the 2 flavours of the webapp. Only the client dependency changes between the 2 pom files. Here is an excerpt of one of them :
<dependencies>
<dependency>
<groupId>com.storage</groupId>
<artifactId>client</artifactId>
<version>${project.version}</version>
</dependency>
<dependency>
<groupId>com.group.id</groupId>
<artifactId>webapp</artifactId>
<version>${project.version}</version>
<classifier>classes</classifier>
<type>jar</type>
</dependency>
<dependency>
<groupId>com.group.id</groupId>
<artifactId>webapp</artifactId>
<version>${project.version}</version>
<type>war</type>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-install-plugin</artifactId>
<configuration>
<skip>true</skip>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-deploy-plugin</artifactId>
<configuration>
<skip>true</skip>
</configuration>
</plugin>
</plugins>
</build>

Maven Tomcat7 run a dependency war

I have a question regarding maven and its tomcat7 plugin :)
I have the following maven projects:
plugin1: plain java project packaged as jar
plugin2: plain java project packaged as jar
webapp: standalone webapp project packaged as jar
those three project are properly build in maven and the outcome works fine:
I can use the jars from plugin1/plugin2
I can deploy the webapp war file to a web container
I can run tomcat7:run to start the webapp
Now, I need to provide different packaging of the webapp containing specific plugin setup.
i.e. I want to generate a war file with webapp + plugin1 and another one with webapp + pugin2
To achieve this, I have created 2 additionnal maven projects that declare dependancies on the webapp project + the appropriate plugin projects and are packaged as wars.
The generated war files have the expected content, and can be deployed to a tomcat, but when I try to use the maven tomcat plugin (tomcat7:run again), it simply doesnt start anything.
Though this is not blocking for me (my main point was to generate the war files), I have the feeling that I missed something.
the pom.xml for those aggregate projects looks like this (note that there is absolutly no code in those projects, these were just created for packaging with specific dependancies convenience).
<groupId>my.project</groupId>
<artifactId>live1</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>MyWebapp</name>
<properties>
<failOnMissingWebXml>false</failOnMissingWebXml>
</properties>
<dependencies>
<dependency>
<groupId>my.project</groupId>
<artifactId>plugin1</artifactId>
<version>${project.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>my.project</groupId>
<artifactId>webapp</artifactId>
<version>${project.version}</version>
<type>war</type>
<scope>runtime</scope>
</dependency>
</dependencies>
<build>
<finalName>MyWebapp</finalName>
<plugins>
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.0</version>
<configuration>
<url>http://localhost:8080/manager</url>
<server>localhost</server>
<path>/${project.build.finalName}</path>
</configuration>
</plugin>
</plugins>
</build>
Thanks !
note: long time lurker, first time asker here, if some information is missing tell me :)

Depending on the structure of your project it may not be suficient to just add a dependency of type war. You may need also to configure <overlays> as described here maven-war-plugin.
It looks like your final war does not provide the full web configuration that you expect. With overlays you can configure how the resources from the dependency will be packed into your final web app.
There must be some difference in the way that your external tomcat starts the app compared to the tomcat7 plugin. May be you can try -X option :
mvn -X tomcat7:run
This should log out some details, of what the embedded tomcat is configuring..

Maven GWT 2.0 and Eclipse

Does anyone know of a good guide for creating a project with the new 2.0 release of GWT using maven and eclipse? I am running into a lot of problems getting them to play nicely together.
For what it's worth, I can create a gwt project using the maven eclipse plugin which works fine, but porting it to maven doesn't work (so a guide for this would be great).
Likewise, I can use the maven plugin (gwt-maven-plugin), but when I import it to eclipse (import -> materialize maven projects), it does not get recognised as a GWT project...
Thanks

EDIT: I've updated my answer with additional steps provided by the OP. Credits to the OP for the details.
I just broke my Eclipse setup trying to install the latest version of the Google Plugin for Eclipse (for GWT 2.0) so I can't confirm everything but, let's assume the following prerequisites are fulfilled:
Eclipse 3.5
Google Plugin for Eclipse (installed from http://dl.google.com/eclipse/plugin/3.5, see instructions)
m2eclipse Plugin for Eclipse (installed from http://m2eclipse.sonatype.org/update)
Did you try to:
Create a new project from Eclipse (New > Other... then select Maven Project and choose the gwt-maven-plugin archetype).
Edit the generated pom.xml, update the gwt.version property to 2.0.0 (which has been released in the central repo), add the Codehaus Snapshot repository and set the gwt-maven-plugin version to 1.2-SNAPSHOT (the version 1.2 isn't released in central, this should happen soon) 1.2 (which has been released in central too).
Add a <runTarget> to the gwt-maven-plugin configuration as documented in Using the Google Eclipse Plugin.
Configure the maven-war-plugin as documented in the page mentioned in the previous step.
Manually enable GWT on the project from project preference by setting the Use Google Web Toolkit checkbox This step is unnecessary since you'll be building/running with a Maven run configuration, not the GWT Plugin for Eclipse.
This is how my pom.xml actually looks like:
<?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">
<!--
GWT-Maven archetype generated POM
-->
<modelVersion>4.0.0</modelVersion>
<groupId>com.mycompany.demo</groupId>
<artifactId>my-gwtapp</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>gwt-maven-archetype-project</name>
<properties>
<!-- convenience to define GWT version in one place -->
<gwt.version>2.0.0</gwt.version>
<!-- tell the compiler we can use 1.5 -->
<maven.compiler.source>1.5</maven.compiler.source>
<maven.compiler.target>1.5</maven.compiler.target>
</properties>
<dependencies>
<!-- GWT dependencies (from central repo) -->
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-servlet</artifactId>
<version>${gwt.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.google.gwt</groupId>
<artifactId>gwt-user</artifactId>
<version>${gwt.version}</version>
<scope>provided</scope>
</dependency>
<!-- test -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.4</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<outputDirectory>war/WEB-INF/classes</outputDirectory>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>gwt-maven-plugin</artifactId>
<version>1.2</version>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>generateAsync</goal>
<goal>test</goal>
</goals>
</execution>
</executions>
<configuration>
<runTarget>com.mycompany.demo.gwt.Application/Application.html</runTarget>
</configuration>
</plugin>
<!--
If you want to use the target/web.xml file mergewebxml produces,
tell the war plugin to use it.
Also, exclude what you want from the final artifact here.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<configuration>
<webXml>target/web.xml</webXml>
<warSourceExcludes>.gwt-tmp/**</warSourceExcludes>
</configuration>
</plugin>
-->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.0.2</version>
<configuration>
<warSourceDirectory>war</warSourceDirectory>
<webXml>src/main/webapp/WEB-INF/web.xml</webXml>
</configuration>
</plugin>
</plugins>
</build>
</project>
Run the gwt:eclipse goal (using m2eclipse Maven2 > build...) to setup your environment and create the launch configuration for your GWT modules.
Run gwt:compile gwt:run to compile and run a GWT module in the GWT Hosted mode.

You can run the following command to generate a Maven GWT project:
webAppCreator -maven -noant -out
For more information:
GWT webappcreator creating a Maven project: the source attachment does not contain the source for the file URLClassPath.class

Just in case. If you use Google GIN in your project you should add compile goal before gwt:compile. So the whole sequence would be:
compile gwt:compile gwt:run
You can read explanation here:
http://code.google.com/p/google-gin/wiki/GinTutorial#Compilation

An annoying problem with GWT and m2eclipse:
GWT Development Mode requires all JARs
to be placed in WEB-INF/lib. It's
especially painful when programmers
use m2eclipse, which provides its own
Eclipse classpath container.
http://code.google.com/p/google-web-toolkit/issues/detail?id=5693
good news, the workaround is working for me

very useful thread
#Pascal: thank you (I donot have enough reputations to comment on others posts; so here I am posting on what is working for me).
I needed 2.5.1 GWT (not 2.6, the latest) working with maven and eclipse (because sencha GXT is not supported for 2.6 yet). Tried following without luck
1)tried few archetypes with in eclipse to generate the project
2)modify pom file (based on above discussion) to change versions to 2.5.1
Following worked for me http://mojo.codehaus.org/gwt-maven-plugin/user-guide/archetype.html
mvn archetype:generate -DarchetypeGroupId=org.codehaus.mojo -DarchetypeArtifactId=gwt-maven-plugin -DarchetypeVersion=2.5.1
mvn gwt:eclipse
mvn gwt:run