Is there a proper way of doing this maybe through a command line? Or do I really have to modify the POM file itself? Let's say I want to install the maven war plugin into an existing project. I tried googling but I can only find the usage and not the installation to an existing project.
As documented here,
Maven is - at its heart - a plugin execution framework; all work is
done by plugins.
You must mean invoking or using a plugin than installing a plugin. You can invoke pretty much any maven plugin without updating the pom, so long as you are ok with the default configurations.
For instance, to generate a javadoc on a maven project, you could just type
mvn javadoc:javadoc
Now, coming to maven war plugin. This creates a war artifact of your project. It makes no sense to invoke it on a project, unless the project is a war project. If it is so, the packaging of the project should be war.
<packaging>war</packaging>
In this case, maven war plugin gets automatically invoked on it.
If you want to customize/configure a plugin or based on the type of plugin, you declare it in your pom (in <plugins> section and do the configurations).
You add the plugin to the POM.
Maven configuration is done via the POM; it's kind of the point--the POM defines the project.
Related
I am using Maven to use Postrgres SQL driver. Besides I am using InteliJ IDEA Ultimatre Edition, and, as I understood, Maven is included in Ultimate version initially. Correct me - all I need, is to set dependencies, and connect PostrgeSQL to Java. I am not oblige to Download Maven (except required Dependecie of course, I mean Maven as framework)? Thanks a lot!
When you are creating a new project, choose Maven. After the project is created, you will receive an empty Maven project structure with the pom.xml and a script mvnw of Maven Wrapper, which you can use (instead of mvn) to build your app.
Just add dependencies to the pom.xml and build.
The Maven Wrapper will do the work for you - download Maven into the project subdirectory and use it.
What is the exact dependency I need to develop a Gradle Plugin in Java? Ideally I would like to get it from a well-known repository such as Maven Central or similar.
I have a Maven project with a core functionality and I just added two extra plugins, one for Ant, one for Maven. They are already tested and working; easy! Now, I wanted to add a third module for a Gradle plugin to make this functionality also available from any Gradle project.
However, I can't find the exact dependencies I need to develop a Gradle plugin.
The Gradle docs (such as https://docs.gradle.org/current/userguide/java_gradle_plugin.html) are not very well written to say the least. They mention:
the gradleAPI() dependency
or the java-gradle-plugin dependency
But they are quite unclear... no group, no version (really?).
If anyone can enlighten me to where I can get these dependencies from, I would be very thankful.
Gradle's public and internal APIs, aka gradleApi(), are bundled with the Gradle distribution and not independently published and therefore not easily consumable by Maven builds. There's the pending epic #1156 (Ensure plugin cross-version compatibility by allowing a user to depend on gradlePublicApi()) that might help here.
Since Gradle plugins are best to be built with Gradle, a pragmatic solution is to invoke the Gradle build from Maven and attach the produced artifact to the Maven build. Andres Almiray (aalmiray) once described this in the blog post Running Gradle Inside Maven (Web Archive Link). He describes the following high level steps:
Create a new Maven module (e.g. gradle-plugin) and add attach it to the parent POM
In the POM of gradle-plugin add a dependency to your core module. Use the maven-dependency-plugin to store dependencies to the Maven build folder, e.g. target/dependencies.
Create the build.gradle, add a Maven repository that points to target/dependencies (step 2) and let it depend on the core module as well as gradleApi(). Implement the Gradle plugin.
Use the exec-maven-plugin to invoke the Gradle build.
Use the maven-resources-plugin to copy the Gradle built plugin jars to the standard Maven build folder.
Use the build-helper-maven-plugin to attach the copied jars to the Maven build.
Sample project to be found here (gradle-in-maven).
https://docs.gradle.org/current/userguide/custom_plugins.html#sec:custom_plugins_standalone_project
In here it is mentioned that it is gradleApi() and I know that this works (from experience). The localGroovy() on that page is only needed if your plugin code uses groovy (does not apply if you only use groovy in the build.gradle of your plugin).
java-gradle-plugin is a library that makes it a bit simpler to make plugins, it is not required though. I personally prefer using gradleApi only.
EDIT:
It appears I've misunderstood the question. Here are the steps to get gradleApi jar:
Create a Gradle project with your desired Gradle version.
Add implementation gradleApi() dependency.
Import/run the project once.
Go to your .gradle folder (located in home folder in Linux-based operating systems).
Open caches folder
Open the version folder you want, e.g. 6.0.1
Open generated-gradle-jars folder.
Copy the jar to wherever you want and use it.
For me the 6.0.1 jar is at ~/.gradle/caches/6.0.1/generated-gradle-jars/gradle-api-6.0.1.jar
Please note that I have not tested this, I know the jar is there but I haven't tried using it.
I am having a java project with a ant build file, using this ant file i create an ejb of the project and deploy it on the jboss server.
Now I am planning to use maven and convert this existing project which consist of nearly 28-30 jar's in its class path(jars related to ejb3, hibernate, jboss, etc).
I can easily do it using eclipse i.e right click project goto maven and click Conver to Maven.
A pom.xml is generated and the MavenClassPath Container is also added to the project.
Now I want to know how to get rid of those 28-30 jar's present in the lib folder of the project and in the classpath. i.e. I want my pom.xml handle all the dependencies.
Does Maven provide any mechanism to achieve this goal while converting the project or I have to add all of these jar dependencies one by one manually in the pom.xml file.
The intention of doing this is I want to have common maven remote repository where the jars will be stored and each developer machine will point to it through their maven project.
Thanks
I think you're after a repository manager like Nexus (I use Nexus, it seems to be the most popular http://nexus.sonatype.org/ ).
Nexus can be used as:
A proxy repository (for Maven Central, etc)
A repository for your own releases.
Nexus provides user management for your developers to release builds into the repo.
Developers will then point their Maven settings.xml file to your Nexus repository, and all their dependencies will come from here (Nexus will cache them).
I'm afraid you will have to configure the dependencies individually, but that is a good thing, because you should pay attention to what version ranges you are interested in for each dependency.
Any jars which can't be found in Maven Central, etc, you can add to your own Nexus repository .
Ofcourse there are alternatives to Nexus, but I haven't used any.
HTH
The most important thing i can recommend is to use a Maven Repository Manager (Nexus, Artifactory or Achiva or other..).
Second your pom conversion via Eclipse shows me that you are not using an up-to-date Eclipse nor an up-to-date Maven Plugin for Eclipse. The best thing would be use Eclipse-Indigo (m2e is the newest and greatest).
Furthermore you have to go through all your jar's and add them step by step to you pom (dependencies) and see if your project can be compiled. This should be checked on command line not inside Eclipse.
After you got a working pom.xml file put it into your version control and check if you can remove some of your added dependencies based on transitive dependencies. After that you can finally delete your lib folder.
I've got a war which I'm trying to reduce the dependencies contained in it's WEB-INF/lib as they're provided by the ear and if they're only in the ear it resolves some classloader issues I've had.
If I run mvn clean install in the module for the war it builds in only the dependencies I want. If I go up a level and run mvn install on the project (the war's defined as a module in the pom.xml at this level) then the war is repackaged with a lot more dependencies.
Why would the behaviour be different and how can I stop all these extra dependencies getting in?
I've tried following the advice here but saw no difference in the behaviour: http://maven.apache.org/plugins/maven-war-plugin/examples/skinny-wars.html
Maven 2.0.6, maven-ear-plugin 2.4.1, maven-war-plugin 2.1-beta-1 (I can't change the versions, I'm on a closed network). Thanks in advance.
ETA: A mvn clean install at the project level gives me the results I want. An mvn clean and then an mvn install adds in the extra jars that I don't want.
Run mvn dependency:tree to see where the (probably transitive) dependencies are coming in from.
You'll want to read "Maven the Definitive Guide" (free PDF by Sonatype) in order to get an in depth understanding of how Maven deals with Dependency management.
And please do find a way to upgrade to maven 2.1.0 (preferably 2.2.1), and the latest versions of the plugins, earlier versions are notoriously buggy.
I'm in the process of learning maven (and java packaging & distribution) with a new oss project I'm making as practice. Here's my situation, all java of course:
My main project is ProjectA, maven-based in a github repository. I have also created one utility project, maven-based, in github: ProjectB. ProjectA depends on a project I have heavily modified that originally was from a google-code ant-based repository, ProjectC.
So, how do I set up the build for ProjectA such that someone can download ProjectA.jar and use it without needing to install jars for ProjectB and ProjectC, and also how do I set up the build such that someone could check out ProjectA and run only 'mvn package' for a full compile?
(Additionally, what should I do with my modified version of ProjectC? include the class files directly into ProjectA, or fork the project into something that could then be used by as a maven dependency?)
I've been reading around, links such as this SO question and this SO question, but I'm unclear how those relate to my particular circumstance. So, any help would be appreciated. Thanks!
So, how do I set up the build for ProjectA such that someone can download ProjectA.jar and use it without needing to install jars for ProjectB and ProjectC
Assuming ProjectA is a JAR, you can create an executable JAR that bundles the dependencies with the Maven Assembly Plugin (and the predefined jar-with-dependencies descriptor) or with the Maven Shade Plugin.
how do I set up the build such that someone could check out ProjectA and run only 'mvn package' for a full compile?
You have to deploy the dependencies to a repository that can be read over HTTP and to declare this repository in your pom.xml. AFAIK, git-hub doesn't offer any facility for that. But any web hosting service with FTP access (or better, scp) should do the trick. If your project is open source, another option would be to use Sonatype's OSS Repository Hosting service.
Just in case, you might want to read this blog post but you won't learn much more things.
The easiest would still be to organize the 3 projects as a multi-modules maven project and to build all modules.
Additionally, what should I do with my modified version of ProjectC?
From a modularization point of view (assuming you found a solution for the above part about repository), it would certainly make sense to have it as a separate module, especially if there is an opportunity someone can use ProjectC outside your project.
You have to publish the code from the additional dependencies. Two options:
Use the maven-shade-plugin to create a maven artifact containing all the content of the B and C jars, and publish that under your own G/A/V coordinates.
Publish copies of B and C under your own G/A/V coordinates using the maven-deploy-plugin to your forge just as you will publish your own code. Different forges have different policies; but if you abide by the licenses of B and C you should be OK.