My Maven project uses a forked JAR of spring-security-oauth.
I'd like to add extra debugging statements, so I unzipped the spring-security-oauth-custom.jar.
But, when I navigated to the org/springframework/security/oauth/common/signature directory, I saw class files.
How can I use the source files instead since I can't modify the class files?
Artifacts in Maven are immutable. Assuming you let Maven grab spring-security-oauth-custom.jar from a Maven repository, you can't just edit the contents of the JAR file and expect things to work.
You'll have to do the following:
Download the source bundle for spring-security-oauth-custom.jar.
Expand the sources somewhere.
Make your modifications.
Create a new artifact out of this new module (including creating a new POM file for it, giving it unique Maven coordinations such as groupId, artifactId and version).
Install the new artifact in your own artifact repository.
Adjust your calling module (that is, the module calling spring-security-oauth-custom) to depend on your modified version, instead of the original.
To use a custom built JAR file like that you should deploy it in your local repository and use it as a regular dependency. You can either put it in your repository manually, or you can use the maven-install-plugin. Either way, you should create a unique version number for it so it does not "collide" with any official Spring artifacts.
Related
I want to publish my Java project on GitHub. I'm not sure if I should upload my pom.xml from Maven in my repository.
I'm using Eclipse without eGit.
On the one hand:
the pom.xml is necessary to know which libraries I used.
On the other hand:
it's a configuration file which maybe shouldn't made public.
it destroys the look of a clean repo, because it's outside of the normal source files.
What should I do best?
it's a configuration file which maybe shouldn't made public.
This is wrong. The POM is indeed a configuration file but it is intended for this file to be public. Actually, quoting Maven guide to uploading artifacts to the Central Repository:
Some folks have asked why do we require all this information in the POM for deployed artifacts so here's a small explanation. The POM being deployed with the artifact is part of the process to make transitive dependencies a reality in Maven. The logic for getting transitive dependencies working is really not that hard, the problem is getting the data. The other applications that are made possible by having all the POMs available for artifacts are vast, so by placing them into the repository as part of the process we open up the doors to new ideas that involve unified access to project POMs.
As you see, this file is actually required so that the artifact can be uploaded to Maven Central.
What should not be public is your settings, i.e. the settings.xml file. It is in this file that you should store any sensitive information, like passwords. Again, quoting the Settings Reference (emphasis mine):
The settings element in the settings.xml file contains elements used to define values which configure Maven execution in various ways, like the pom.xml, but should not be bundled to any specific project, or distributed to an audience. These include values such as the local repository location, alternate remote repository servers, and authentication information.
If you currently store any sensitive information in your POM, you should consider refactoring it to extract this info and put it inside your settings instead.
it destroys the look of a clean repo, because it's outside of the normal source files.
It is a source file in the sense that Maven only requirement is exactly the presence of this file. It describes how to build your application and declares all of its dependencies. To say it differently: this file is a Maven source file, and as such, should be commited along with the project main source files. Without it, no-one can build your application and no-one can also package it.
I have a java maven project that has another module as a dependency.
That dependency has "-sources.jar" in the repository (and I can download the sources with mvn dependency:sources)
I now need to do some little one-line changes in the module I am using as a dependency. The ideal way would be to somehow copy this dependency as another module, with all its current sub-dependencies. Then when I build the whole project, I want to build my newly copied dependency and use it instead of the current dependency. (I hope it's clear what I want to do.)
However, I don't know at all how to do that, and if it's even possible.
edit:
To be clearer.
I have my own project. I am also using let's say com.example.dependency from a repository. There are however small bugs in the com.example.dependency module, so I want to download the source to me and fix it locally and use it as a submodule.
edit2:
I will add that the dependency is not any public project on github, etc. It is a module in a private maven repository that only I have an access to. I cannot clone the source control project. I can only use maven, and its dependency tracking, and the "dependency:sources" thing.
what you may to to do is to checkout your dependency source as new project and do the changes. Then modify your project version and do the
mvn install
to install it in your local repository, then you this version in your project as one of the dependency, you will add this dependency in usual way you have done earlier, but change the version to new version you have installed.
One of the 3rd party libraries used in my company is supplied to us as a zip file with tens of jars in it. The library releases a new version every two weeks, so I am looking for a solution that does not require a lot of manual effort each time a new release is out. I have recently started using Maven for dependency management and I have found it very difficult to deal with this particular 3rd party library. Should I...
add each individual jar to a company-internal repository (e.g. with Nexus) and then declare each one of them as a dependency to any new projects using this library? This is a laborious process and I can't imagine doing this for every new release.
create a jar of jars to add to our repository? If so, how do I create it? The Maven shade plugin would require that I mavenise the library first, right?
any better suggestions?
Your first option is the best practice. I'm not sure why it should be laborious.
create a simple script to upload the various jars to nexus
use a property in your pom to specify the third-party version so all deps can be changed with a simple property change in the pom
Should be all of 5 minutes to add a new release to your build pipeline.
Alternative: convince the third-party to setup a maven repository for their customers to use!
Its possible, but complicated (but only a 1 time effort) and probably a misuse of what maven's meant for:
Upload zip file to your local maven repo with a specific groupid:artifactId
Create a sub-module that has dependency on this zip file. Tis sub module should be used only for creating the uber jar
Use maven-dependency-plugin unpack goal to unpack the zip file into a directory
Use maven antrun unzip to unzip the jars to a dir
Use maven antrun zip to jar the files into a uber jar
Use maven-intall-plugin to install uber jar to your local repo and use as a dependency.
I was given a maven project to compile and get deployed on a tomcat server. I have never used maven before today, but I have been googling quite a bit. It seems like the top level pom.xml files in this project have the packaging type set as pom.
What am I supposed to do after mvn install to get this application deployed? I was expecting to be able to find a war file somewhere or something, but I guess I am looking in the wrong place or missing a step.
pom is basically a container of submodules, each submodule is represented by a subdirectory in the same directory as pom.xml with pom packaging.
Somewhere, nested within the project structure you will find artifacts (modules) with war packaging. Maven generally builds everything into /target subdirectories of each module. So after mvn install look into target subdirectory in a module with war packaging.
Of course:
$ find . -iname "*.war"
works equally well ;-).
pom packaging is simply a specification that states the primary artifact is not a war or jar, but the pom.xml itself.
Often it is used in conjunction with "modules" which are typically contained in sub-directories of the project in question; however, it may also be used in certain scenarios where no primary binary was meant to be built, all the other important artifacts have been declared as secondary artifacts
Think of a "documentation" project, the primary artifact might be a PDF, but it's already built, and the work to declare it as a secondary artifact might be desired over the configuration to tell maven how to build a PDF that doesn't need compiled.
Packaging of pom is used in projects that aggregate other projects, and in projects whose only useful output is an attached artifact from some plugin. In your case, I'd guess that your top-level pom includes <modules>...</modules> to aggregate other directories, and the actual output is the result of one of the other (probably sub-) directories. It will, if coded sensibly for this purpose, have a packaging of war.
To simply answer your question when you do a mvn:install, maven will create a packaged artifact based on (packaging attribute in pom.xml), After you run your maven install you can find the file with .package extension
In target directory of the project workspace
Also where your maven 2 local repository is search for (.m2/respository) on your box, Your artifact is listed in .m2 repository under (groupId/artifactId/artifactId-version.packaging) directory
If you look under the directory you will find packaged extension file and also pom extension (pom extension is basically the pom.xml used to generate this package)
If your maven project is multi-module each module will two files as described above except for the top level project that will only have a pom
Packaging an artifact as POM means that it has a very simple lifecycle
package -> install -> deploy
http://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html
This is useful if you are deploying a pom.xml file or a project that doesn't fit with the other packaging types.
We use pom packaging for many of our projects and bind extra phases and goals as appropriate.
For example some of our applications use:
prepare-package -> test -> package -> install -> deploy
When you mvn install the application it should add it to your locally .m2 repository. To publish elsewhere you will need to set up correct distribution management information. You may also need to use the maven builder helper plugin, if artifacts aren't automatically attached to by Maven.
I suggest to see the classic example at: http://maven.apache.org/guides/getting-started/index.html#How_do_I_build_more_than_one_project_at_once
Here my-webapp is web project, which depends on the code at my-app project. So to bundle two projects in one, we have top level pom.xml which mentions which are the projects (modules as per maven terminology) to be bundled finally. Such top level pom.xml can use pom packaging.
my-webapp can have war packaging and can have dependency on my-app. my-app can have jar packaging.
“pom” packaging is nothing but the container, which contains other packages/modules like jar, war, and ear.
if you perform any operation on outer package/container like mvn clean compile install. then inner packages/modules also get clean compile install.
no need to perform a separate operation for each package/module.
Real life use case
At a Java-heavy company we had a python project that needed to go into a Nexus artifact repository. Python doesn't really have binaries, so simply just wanted to .tar or .zip the python files and push. The repo already had maven integration, so we used <packaging>pom</packaging> designator with the maven assembly plugin to package the python project as a .zip and upload it.
The steps are outlined in this SO post
https://maven.apache.org/pom.html
The packaging type required to be pom for parent and aggregation (multi-module) projects. These types define the goals bound to a set of lifecycle stages. For example, if packaging is jar, then the package phase will execute the jar:jar goal. If the packaging is pom, the goal executed will be site:attach-descriptor
POM(Project Object Model) is nothing but the automation script for building the project,we can write the automation script in XML,
the building script files are named diffrenetly in different Automation tools
like we call build.xml in ANT,pom.xml in MAVEN
MAVEN can packages jars,wars, ears and POM which new thing to all of us
if you want check WHAT IS POM.XML
What is an artifact and why does Maven need it?
An artifact is a file, usually a JAR, that gets deployed to a Maven repository.
A Maven build produces one or more artifacts, such as a compiled JAR and a "sources" JAR.
Each artifact has a group ID (usually a reversed domain name, like com.example.foo), an artifact ID (just a name), and a version string. The three together uniquely identify the artifact.
A project's dependencies are specified as artifacts.
In general software terms, an "artifact" is something produced by the software development process, whether it be software related documentation or an executable file.
In Maven terminology, the artifact is the resulting output of the maven build, generally a jar or war or other executable file. Artifacts in maven are identified by a coordinate system of groupId, artifactId, and version. Maven uses the groupId, artifactId, and version to identify dependencies (usually other jar files) needed to build and run your code.
I know this is an ancient thread but I wanted to add a few nuances.
There are Maven artifacts, repository manager artifacts and then there are Maven Artifacts.
A Maven artifact is just as other commenters/responders say: it is a thing that is spat out by building a Maven project. That could be a .jar file, or a .war file, or a .zip file, or a .dll, or what have you.
A repository manager artifact is a thing that is, well, managed by a repository manager. A repository manager is basically a highly performant naming service for software executables and libraries. A repository manager doesn't care where its artifacts come from (maybe they came from a Maven build, or a local file, or an Ant build, or a by-hand compilation...).
A Maven Artifact is a Java class that represents the kind of "name" that gets dereferenced by a repository manager into a repository manager artifact. When used in this sense, an Artifact is just a glorified name made up of such parts as groupId, artifactId, version, scope, classifier and so on.
To put it all together:
Your Maven project probably depends on several Artifacts by way of its <dependency> elements.
Maven interacts with a repository manager to resolve those Artifacts into files by instructing the repository manager to send it some repository manager artifacts that correspond to the internal Artifacts.
Finally, after resolution, Maven builds your project and produces a Maven artifact. You may choose to "turn this into" a repository manager artifact by, in turn, using whatever tool you like, sending it to the repository manager with enough coordinating information that other people can find it when they ask the repository manager for it.
Hope that helps.
Maven organizes its build in projects.
An artifact in maven is a resource generated by a maven project. Each maven project can have exactly one artifact like a jar, war, ear, etc.
The project's configuration file "pom.xml" describes how the artifact is build, how unit tests are run, etc.
Commonly a software project build with maven consists of many maven-projects that build artifacts (e.g. jars) that constitute the product.
E.g.
Root-Project // produces no artifact, simply triggers the build of the other projects
App-Project // The application, that uses the libraries
Lib1-Project // A project that creates a library (jar)
Lib2-Project // Another library
Doc-Project // A project that generates the user documentation from some resources
Maven artifacts are not limited to java resources. You can generate whatever resource you need. E.g. documentation, project-site, zip-archives, native-libraries, etc.
Each maven project has a unique identifier consiting of [groupId, artifactId, version]. When a maven project requires resources of another project a dependency is configured in it's pom.xml using the above-mentioned identifier. Maven then automatically resolves the dependencies when a build is triggered. The artifacts of the required projects are then loaded either from the local repository, which is a simple directory in your user's home, or from other (remote) repositories specified in you pom.xml.
Q. What is Artifact in maven?
ANS: ARTIFACT is a JAR,(WAR or EAR), but it could be also something else. Each artifact has,
a group ID (like com.your.package),
an artifact ID (just a name), and
a version string. The three together uniquely identify the artifact.
Q.Why does Maven need them?
Ans: Maven is used to make them available for our applications.
An artifact is a JAR or something that you store in a repository. Maven gets them out and builds your code.
To maven, the build process is arranged as a set of artifacts. Artifacts include:
The plugins that make up Maven itself.
Dependencies that your code depends on.
Anything that your build produces that can, in turn be consumed by something else.
Artifacts live in repositories.
usually we talking Maven Terminology about Group Id , Artifact Id and Snapshot Version
Group Id:identity of the group of the project
Artifact Id:identity of the project
Snapshot version:the version used by the project.
Artifact is nothing but some resulting file like Jar, War, Ear....
simply says Artifacts are nothing but packages.
Usually, when you create a Java project you want to use functionalities made in another Java projects.
For example, if your project wants to send one email you dont need to create all the necessary code for doing that. You can bring a java library that does the most part of the work.
Maven is a building tool that will help you in several tasks. One of those tasks is to bring these external dependencies or artifacts to your project in an automatic way ( only with some configuration in a XML file ).
Of course Maven has more details but, for your question this is enough.
And, of course too, Maven can build your project as an artifact (usually a jar file ) that can be used or imported in other projects.
This website has several articles talking about Maven :
https://connected2know.com/programming/what-is-maven/
https://connected2know.com/programming/maven-configuration/
An artifact is an element that a project can either use or produce. In Maven terminology, an artifact is an output generated after a Maven project build. It can be, for example, a jar, war, or any other executable file.
Also, Maven artifacts include five key elements, groupId, artifactId, version, packaging, and classifier. Those are the elements we use to identify the artifact and are known as Maven coordinates.
read it from here