We Keep Coding

Adding Javalin dependencies

I'm trying to use Javalin in my project and I can't seem to understand how to add the needed dependencies in order to work with Javalin without compliation errors.
The project i'm working on is not a Maven project, it is a simple Java project so it won't be downloaded automatically.
How do I add the dependencies and where?
I am using VSCode but can Switch to Intellij IDEA if needed.
Thanks.

At the risk of pointing you in a direction you may not want to go in... Use a dependency manager (Maven, Gradle, Ivy, or similar). Simple Java projects can be dependency-managed projects, too!
A basic Javalin project includes dozens of dependencies - and dependencies of those dependencies... You will probably have an unpleasant time attempting to handle them all manually, one-by-one.
If you use the Javalin bundle, that will take care of all of this for you.
To give you a sense of what I mean:
If you do decide to use a dependency manager, then your follow-up questions are well covered elsewhere. Or you can ask a follow-up, based on any problems you may encounter.
Update
Yeah but were doing it in a school project and were already half way through the project and now I need to add a Web Client and we don't want to change things all through the project, there's gotta be a way to add those dependencies without creating a new Maven project for it.
You can install Maven and run a command to download all the JARs to a directory.
This is (in my opinion) more work than just using Maven already built into all mainstream IDEs, but here are the steps:
Note: My set-up assumes Windows. You can adjust as needed for Linux or a different OS.
Download Maven - see here.
I downloaded the binary zip archive.
Set up Maven - see here.
Be sure to pay particular attention to the instructions regarding setting the JAVA_HOME environment variable pointing to your JDK installation or having the java executable on your PATH.
I installed my Maven here:
C:\maven\apache-maven-3.8.5
I tested it in a shell using the mvn -v command:
C:\maven\apache-maven-3.8.5\bin\mvn -v
Create a pom.xml file. Maven uses this as its instructions for what to download (and to what location).
In my case I created the POM here:
C:\maven\demo\pom.xml
Its contents are:
<?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>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
</properties>
<groupId>org.andrewjames</groupId>
<artifactId>my-Javalin-demo</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>io.javalin</groupId>
<artifactId>javalin-bundle</artifactId>
<version>4.5.0</version>
</dependency>
</dependencies>
<build>
<finalName>my-Javalin-demo</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.3.0</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<silent>true</silent>
<outputDirectory>C:/maven/demo</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
<name>my-Javalin-demo</name>
</project>
The maven.compiler sections assume I have Java 17 available. You may need to adjust to match your Java version.
The dependencies section is where the javalin-bundle is defined.
The execution section is the directive which causes all dependency JARs to be downloaded to the Maven local repository, and then copied to a new directory.
In my case the new directory will be created here:
C:\maven\demo\target\dependency
Open a CMD shell and cd to C:\maven\demo
At the command line, run the following command:
C:\maven\apache-maven-3.8.5\bin\mvn dependency:copy-dependencies
After that has completed, you will see approx. 100 JAR files in the C:\maven\demo\target\dependency directory.

Maven multi module: error assembling WAR: webxml attribute is required

I'm turning a single Eclipse Maven-managed webapp project in a multi-module Maven project (this is a test project to experiment with Maven, so feel free to provide any kind of suggestion).
The single project webapp doean't have any error, succesfully compiles and behaves correctly when deployed, so I'm starting with a working application.
The application has a web part and a console part, meaning that there are some classes with a main() method that when run from within Eclipse (with Run as -> Java Application) work as expected. Both parts show data from a database, queried either directly through JDBC or through jOOQ.
So, this is how I split the project:
core (holds everything common to the other two parts);
runnable (contains the classes that have a main() method);
webapp (the web application part).
Inside Eclipse, I have now 4 separate projects:
shaker-multi holds the aggregator (and parent) POM, plus each module in a subdirectory;
shaker-multi-core;
shaker-multi-runnable;
shaker-multi-webapp.
Inside Eclipse, core and webapp compile, and the latter can be deployed to a Tomcat instance and I can see it in the browser.
The problem arises with runnable. That project relies on jOOQ classes, so the relevant source code must be generated. The jOOQ dependencies and configuration are in core/pom.xml (since they may be used there too).
When I do Project -> Run As -> Maven build... -> clean generate-sources, on shaker-multi-core I get:
Non-resolvable parent POM: Failure to find sunshine.web:shaker-multi:pom:0.0.1
which sounds reasonable, since I didn't install any of those artifacts, even in my local repository.
But when I call Maven build... -> 'clean install' on shaker-multi, it breaks because it can't find the web.xml file for shaker-multi-webapp (although it correctly resides in shaker-multi-webapp/src/main/webapp/WEB-INF/web.xml).
What should I do?
Is my project configuration / splitting totally wrong?
Should I add another module with the parent POM? This sounds wrong, since the POM Reference states:
Inheritance and aggregation create a nice dynamic to control builds through a single, high-level POM. You will often see projects that are both parents and aggregators.
I'm totally lost here.
My expectations:
run Maven package on shaker-multi-webapp and obtain a deployable war;
run Maven package on shaker-multi-runnable and obtain a command line runnable jar (I still need to configure its POM to generate a jar-with-dependencies, though, I know);
run Maven package on shaker-multi and obtain some kind of bundle that I can move around and that will contain the war or the jar of each module.
EDIT
I added
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<configuration>
<webXml>src/main/webapp/WEB-INF/web.xml</webXml>
</configuration>
</plugin>
to shaker-multi-webapp POM, as seen in this answer, but with no difference.
EDIT-2
I cleared my whole local repository (as suggested here), and when I reopened Eclipse, in the Maven console I saw
[...]
05/09/14 07:58:19 CEST: [INFO] Adding source folder /shaker-multi-webapp/src/main/java
05/09/14 07:58:19 CEST: [INFO] Adding source folder /shaker-multi-webapp/src/test/java
**05/09/14 07:58:19 CEST: [ERROR] Could not read web.xml**
[...]
Any hint? From where does it come from? I can't reproduce it though (without removing again my whole local repo).
This is shaker-multi POM:
<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>sunshine.web</groupId>
<artifactId>shaker-multi</artifactId>
<version>0.0.1</version>
<packaging>pom</packaging>
<modules>
<module>shaker-multi-core</module>
<module>shaker-multi-runnable</module>
<module>shaker-multi-webapp</module>
</modules>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
</build>
</project>
This is shaker-multi-core POM:
<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>sunshine.web</groupId>
<artifactId>shaker-multi</artifactId>
<version>0.0.1</version>
</parent>
<artifactId>shaker-multi-core</artifactId>
<packaging>jar</packaging>
<build>
<plugins>
<plugin><!-- jOOQ plugin--></plugin>
</plugins>
</build>
<dependencies>
<dependency><!-- jOOQ dependency --></dependency>
</dependencies>
</project>
This is shaker-multi-webapp POM:
<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>sunshine.web</groupId>
<artifactId>shaker-multi</artifactId>
<version>0.0.1</version>
</parent>
<artifactId>shaker-multi-webapp</artifactId>
<packaging>war</packaging>
<build>
<plugins>
<plugin><!-- Tomcat local -->
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>sunshine.web</groupId>
<artifactId>shaker-multi-core</artifactId>
<version>0.0.1</version>
</dependency>
<dependency>
<!-- JSP & Servlet dependencies -->
</dependency>
</dependencies>
</project>

I assume you folder structure is like this:
+-- shaker-multi
+--- pom.xml
+--- shaker-multi-core
+-- pom.xml
+--- shaker-multi-runnable
+-- pom.xml
+--- shaker-multi-webapp
+-- pom.xml
Furthermore you should check if your project works correctly on command and
NOT in Eclipse. So you should go to the root of your project
(shaker-multi folder) and
mvn clean package
This should produce no error etc.
One thing which comes into my mind is why do you use a release version instead of
a SNAPSHOT version for your project. So 0.0.1 instead of 0.0.1-SNAPSHOT?
A thing which you should improve is the definintion of maven-compiler plugin
in your parent:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
</build>
I would suggest to do it this way:
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
The encoding can be solved in a better way just define the following in your pom:
<project>
...
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
...
</project>
The above will define the default value for many plugin like maven-compiler-plugin,
maven-resources-plugin etc.
part from that your structure looks good ...one small improvement i would
suggest is if you define dependencies between your module:
<dependencies>
<dependency>
<groupId>sunshine.web</groupId>
<artifactId>shaker-multi-core</artifactId>
<version>0.0.1</version>
</dependency>
<dependency>
<!-- JSP & Servlet dependencies -->
</dependency>
</dependencies>
I would suggest to define inter module dependencies like this:
<dependencies>
<dependency>
<groupId>sunshine.web</groupId>
<artifactId>shaker-multi-core</artifactId>
<version>${project.version}</version>
</dependency>
<dependency>
<!-- JSP & Servlet dependencies -->
</dependency>
</dependencies>

The whole problem here was really simple, and I feel a bit ashamed about it: but being the first time I did a multi–module project, I guess that could happen.
Of course, the details here hold when you work with all the project and modules sources by yourself: if you're in a team, working on only a part of the project and / or with a centralized private repository, then YMMV.
First of all, after I splitted the single–project into several modules, this was the situation in my Eclipse Project Explorer:
+-- shaker-multi
^--- pom.xml
^--- shaker-multi-core
^-- pom.xml
^-- (other content)
^--- shaker-multi-runnable
^-- pom.xml
^-- (other content)
^--- shaker-multi-webapp
^-- pom.xml
^-- (other content)
+-- shaker-multi-core
^-- pom.xml
+-- shaker-multi-runnable
^-- pom.xml
+-- shaker-multi-webapp
^-- pom.xml
Each +-- is a single, separated, Eclipse project. Each one of them has been singularly checked out from SVN (so they were, in fact, detached from one another).
I was, then, editing something in +-- shaker-multi-runnable and expecting that to work when I was running Maven on +-- shaker-multi, without svn–committing the former and svn–updating the latter.
That's why I kept getting the error in this question!
The proper way to handle such projects, if they come from an originally monolithic project is:
to split the code, resources, etc in subfolders;
to commit every change to the repository;
to erase every involved project in Eclipse.
Next, you go in the SVN Repositories tab of the IDE, expand the repository with the now splitted project and do Check out as Maven project of the parent–project (the one that has modules as subfolders).
If you, like me, are working with a recent version of Subclipse, you'll need the Maven Eclipse (m2e) SCM connector for subclipse 1.10 (svn 1.8) - update site (thanks go to buluschek development, see the last comments on that post), so that you can choose the repository path from the Check out as Maven Project dialog.
With it, you tell Eclipse to checkout the whole project from the parent folder, and the Eclipse automatically:
fetches all the Maven project modules;
creates a project corresponding to the parent–project, where modules are subfolders;
creates a separate project for every single module
links together each module project with the parent project, so that each edit in a module source code, resource, POM, etc is instantly reflected inside the folders of the parent-project.
That point (4) is the key here: although there are several projects, they have been linked together (I guess the same can be done when manually checking out each module folder, although I do not know how).
After having done this, all the Maven problems I had disappeared.

An error while using the License Maven Plugin in a multi module project

Maven project structure
I have a trivial multi module Maven project:
parent-project
child-project1 (war)
child-project2 (jar)
parent-project's pom.xml references both child projects in its <modules> section. Both child projects reference the parent in their <parent> sections.
child-project1 depends on child-project2 (it references it in the <dependencies> section).
The problem
I am trying to use the License Maven Plugin on the parent-project to generates a file containing a list of all dependencies and their licenses:
mvn license:aggregate-add-third-party
I get an error:
Failed to execute goal on project child-project1: Could not resolve dependencies
for project ... child-project1 ... : Could not find artifact ... child-project2 ...
When I comment out the dependency of child-project1 on child-project2 the plugin works with no problem. So I can use the plugin, but I have to comment out the dependency each time I do it.
What is the problem? Is there a way to fix it?

The problem you are facing is that the maven-license-plugin by default looks in your local repository for the child artifacts.
I suppose, your plugin configuration in the parent pom.xml looks like the following:
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>license-maven-plugin</artifactId>
<version>1.6</version>
<configuration>
<!-- your own config goes here -->
</configuration>
</plugin>
</plugins>
You have to install your multi-module project to your local Maven repository using
mvn install
After that, you run
mvn license:aggregate-add-third-party
again and the build will succeed.
If you configured an <execution> in your plugin, this will fail, since the maven-license-plugin by default binds to the generate-resources phase [1] and this is always executed prior to install [2].
Cheers,
PK

Eclipse Kepler Project Configuration

Plugin execution not covered by lifecycle configuration: org.apache.maven.plugins:maven-resources-plugin:2.5:resources (execution: default-resources, phase: process-resources) pom.xml /Project line 1 Maven Project Build Lifecycle Mapping Problem
Here is the POM.xml
<project xmlns="maven.apache.org/POM/4.0.0"; xmlns:xsi="w3.org/2001/XMLSchema-instance"; xsi:schemaLocation="maven.apache.org/POM/4.0.0 maven.apache.org/xsd/maven-4.0.0.xsd">; <modelVersion>4.0.0</modelVersion>
<groupId>Assignment</groupId>
<artifactId>ApsalarAssignment</artifactId>
<version>0.0.1-SNAPSHOT</version>
</project>
I am getting this error on Kepler, Eclipse while making a new Maven Project. Don't know how to figure it out as I am new to Maven as well as Eclipse. Any help would be highly appreciated.

This problem is due to missing <pluginManagement> tag in pom.xml
In order to fix this error in eclipse, you need to <pluginManagement> tag around your <plugins> tag, like shown below.
<build>
<pluginManagement>
<plugins>
<plugin> ... </plugin>
<plugin> ... </plugin>
....
</plugins>
</pluginManagement>
</build>
As per Maven documentation
pluginManagement is an element that is seen along side plugins. Plugin Management contains plugin elements in much the same way,
except that rather than configuring plugin information for this
particular project build, it is intended to configure project builds
that inherit from this one. However, this only configures plugins that
are actually referenced within the plugins element in the children.
The children have every right to override pluginManagement
definitions.
Shishir

How to specify maven's distributionManagement organisation wide?

I'm trying to figure out how to organize many (around 50+) maven2 projects, so that they can deploy into a central nexus repository. When using the mvn deploy goal, one does need to specify the target in the distributionManagement tag like this:
<distributionManagement>
<repository>
<id>nexus-site</id>
<url>http://central_nexus/server</url>
</repository>
</distributionManagement>
Now, i don't want every single pom.xml (of those 50+) to contain this block over and over again. My first though would be the settings.xml file, but it seems it is not possible (by design) to define it there.
So, the first question would be, why is that the case ? If it would be possible i could specify it in the settings.xml in the maven2 distribution, which could be distributed to all developers.
The only possible solution i've found was to create an organisation-wide master-pom project, that does contain these settings, and make all other pom.xml depend on this master-pom via <parent> tag. But this looks kind of strange in multi-module builds:
- master configuration POM (pm)
- Project 1 parent pom (p1 with module 1 and module 2 as modules)
- Project 1 module pom (with pm as parent)
- Project 2 module pom (with pm as parent)
Usually i read in all documentation that the module poms should use the parent pom, not some different one. But after reading the maven website about Inheritance v. Aggregation it is written that it is indeed possible.
One problem i found was with the maven site generation, which does seem to have problems with this setup (modules does not get linked correctly if they have no direct back-reference)
So, is this a valid approach ? Any other, more obvious, simpler solution to the problem ?

The best solution for this is to create a simple parent pom file project (with packaging 'pom') generically for all projects from your organization.
<?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>your.company</groupId>
<artifactId>company-parent</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>pom</packaging>
<distributionManagement>
<repository>
<id>nexus-site</id>
<url>http://central_nexus/server</url>
</repository>
</distributionManagement>
</project>
This can be built, released, and deployed to your local nexus so everyone has access to its artifact.
Now for all projects which you wish to use it, simply include this section:
<parent>
<groupId>your.company</groupId>
<artifactId>company-parent</artifactId>
<version>1.0.0</version>
</parent>
This solution will allow you to easily add other common things to all your company's projects. For instance if you wanted to standardize your JUnit usage to a specific version, this would be the perfect place for that.
If you have projects that use multi-module structures that have their own parent, Maven also supports chaining inheritance so it is perfectly acceptable to make your project's parent pom file refer to your company's parent pom and have the project's child modules not even aware of your company's parent.
I see from your example project structure that you are attempting to put your parent project at the same level as your aggregator pom. If your project needs its own parent, the best approach I have found is to include the parent at the same level as the rest of the modules and have your aggregator pom.xml file at the root of where all your modules' directories exist.
- pom.xml (aggregator)
- project-parent
- project-module1
- project-module2
What you do with this structure is include your parent module in the aggregator and build everything with a mvn install from the root directory.
We use this exact solution at my organization and it has stood the test of time and worked quite well for us.

There's no need for a parent POM.
You can omit the distributionManagement part entirely in your poms and set it either on your build server or in settings.xml.
To do it on the build server, just pass to the mvn command:
-DaltSnapshotDeploymentRepository=snapshots::default::https://YOUR_NEXUS_URL/snapshots
-DaltReleaseDeploymentRepository=releases::default::https://YOUR_NEXUS_URL/releases
See https://maven.apache.org/plugins/maven-deploy-plugin/deploy-mojo.html for details which options can be set.
It's also possible to set this in your settings.xml.
Just create a profile there which is enabled and contains the property.
Example settings.xml:
<settings>
[...]
<profiles>
<profile>
<id>nexus</id>
<properties>
<altSnapshotDeploymentRepository>snapshots::default::https://YOUR_NEXUS_URL/snapshots</altSnapshotDeploymentRepository>
<altReleaseDeploymentRepository>releases::default::https://YOUR_NEXUS_URL/releases</altReleaseDeploymentRepository>
</properties>
</profile>
</profiles>
<activeProfiles>
<activeProfile>nexus</activeProfile>
</activeProfiles>
</settings>
Make sure that credentials for "snapshots" and "releases" are in the <servers> section of your settings.xml
The properties altSnapshotDeploymentRepository and altReleaseDeploymentRepository are introduced with maven-deploy-plugin version 2.8. Older versions will fail with the error message
Deployment failed: repository element was not specified in the POM inside distributionManagement element or in -DaltDeploymentRepository=id::layout::url parameter
To fix this, you can enforce a newer version of the plug-in:
<build>
<pluginManagement>
<plugins>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8</version>
</plugin>
</plugins>
</pluginManagement>
</build>

Regarding the answer from Michael Wyraz, where you use alt*DeploymentRepository parameters in your settings.xml or command line, the format has changed in version 3.0.0 of the maven-deploy-plugin
In the value:
releases::default::https://YOUR_NEXUS_URL/releases
you need to remove the default section, making it:
releases::https://YOUR_NEXUS_URL/releases