Noob question. I'm considering to learn Maven. I understand what it does in general. Let's say I have a Maven Eclipse project. Then I create an executable JAR, and wrap it with launch4j.
Now I have TestProgram.exe file. Will Maven reload the dependencies, whenever there is a there is a new version available? Will the inner structure of the TestProgram.exe change over time as new versions of dependencies are loaded? Or does Maven update dependencies only during the development stage?
Maven is a build tool. One of it's key benefits is that it yields a repeatable build process. It does not become part of your application.
The artefacts that are included in your build are fixed by the dependency versions that you specify in your project object model (aka pom.xml file).
If you need a newer version of one of these dependencies then you must update your pom.xml file and release a new version of your product.
Related
I have a set of applications, all use Maven and the local repository. The applications form a dependency tree using <dependency> in their pom.xml. All of these projects have -SNAPSHOT in their version.
Is it possible for Maven (or some compatible dependency manager) to build an application together with all of its local dependencies whose source changed?
I do not want to create a multi-module project, because:
the projects are exactly libraries, not modules;
I do not want an additional complexity just to have a form of build which is already precisely defined;
I want the process to be dynamic: if a library is mature enough to be put into a remote repository, it would be no more rebuilt with the main project and that's ok.
For now, there is a lot of refactoring, moving code from one library to another etc. and it happens often that substantial parts of the dependency tree need to be rebuilt. I thus need to manually write mvn install in several projects in order to assure that there is no stale code.
No, it doesn't work. Even with a multi-module project, maven does not detect which modules have changed sources in it and which do not.
There was a (flaky) implementation in Maven 2, but it was not continued in 3.x, see How to get maven 3.0 to only build modules with local scm changes
I hoped they would include it again in maven 4, but I didn't see it yet: https://maarten.mulders.it/2020/11/whats-new-in-maven-4/
I once did a similar setup, but had to use shell scripts with some git magic to get it working.
You can also decide to put your libraries in separate repo's from the start, and use the repo tool that google uses for android development: https://github.com/GerritCodeReview/git-repo/blob/main/README.md
Once you run mvn install on the particular Maven project, it will be accessible for all other Maven projects, which are on the same workstation, during dependency collection (before the compile phase).
Official Maven Build Lifecycle description:
install - install the package into the local repository, for use as a dependency in other projects locally
It's not necessary to keep libraries as part of the same project(or have it as a multi-module project). But once you want to share those libraries with your teammates, you would need either to force them installing libraries locally (as you did), or store those libraries at some external repo, like Artifactory or Nexus
I have a maven project(main) with dependency A(com.util.myutil version 0.0.1).
When there is an update on myutil a new version would be released(0.0.2). Now the main project needs to be updated with the dependency 0.0.2. Can this be achieved via maven/jenkins/bitbucket. Currently we are manually changing the version and committing to bitbucket. I want this to be automated.
This would help to great extent since we have a lot of nested dependencies.
If two projects should be always built together, think about establishing ab multi-module project.
If this is not the way for you: You can use Maven goals like versions:use-latest-releases to update all dependencies in a POM.
I am using the hector & astyanax projects. These projects used to require maven, and now astyanax requires gradle.
I would like to statically link one of these projects to my java project (which is not built using maven/gradle). I am not interested in updating the version of astyanax every time they make a new release. I am not interested in mavenizing/gradelizing my own project.
So, two problems arise: 1. Getting the astyanax jars. 2. Getting the depenedency Jars.
At first, not having time to thoroughly understand maven (get off my lawn!), I copied all of the jar files in my global .maven directory into my project, and linked to them. Problem is, it's a pretty messy solution.
Is there an easier way to get all jars needed to use a gradle/maven library? (While I don't mind using gradle to build astyanax, I don't want to use it to build my own project).
Getting jars for distribution, seems like a very basic use case, am I missing a simple way here?
astyanax is published to maven central as com.netflix.astyanax:astyanax:1.56.42. Any build tool (Grails, Maven, Gradle, Buildr, SBT) that resolves from Maven can make a dependency on Astyanax and have its dependencies transitively downloaded. That fact that it's built with Gradle doesn't change how it's consumed.
From your question, it's unclear how you want to resolve these libraries. If you don't want to use a tool (Grails, Maven, Gradle, Buildr, SBT), then you'll have to manually navigate every dependencies and its dependencies from Maven Central. It's quite uncommon for a modern java project to manually download dependencies anymore, the practicalness given the complex dependencies graph make it prohibitive.
For my project, I'm using code from another project found on github. I've included the project as a separate folder in my project. My project uses code from that project, so I want to build that project and include it in my project without really making any changes to that project. So how do I specify in my pom.xml to run the sub-projects pom.xml?
If it helps, here is the repository of the other project that I am using: Soda Java
If you're not planning on changing it, simply download it & build it once using Maven. This will install it into your local repository, and you can simply reference it in your pom without any issue.
If you can find it in an external maven repo somewhere, you wouldn't even have to download & build it.
Only if you're planning on changing it do you need the aggregate project approach.
You create an aggregate project with packaging=pom and a modules element that has one module for the dependency and one module for your project, and you build that.
just a simple question: I need to add a Maven dependency to a Eclipse Plugin project.
The project has not a POM file, so I converted it to a Maven one.
Now I have plugin.xml file and pom.xml file. POM contains the dependency I need to satisfy, but it's ignored; I mean, I can't resolve an import in source code referring to that import.
Can you help me?
ty
I read about Tycho plugin, but online configurations don't work.
If I'm reading this correctly, you've just started by adding a Maven dependency to your project, but don't have the dependency available for Eclipse to validate your code against.
You will need to start a Maven build after you add a brand new dependency so that Maven can add that to your local cached repository. Once the Maven build is done, Eclipse should recognize your imports properly.
You may want to check whether the dependency you are looking for is available in the Eclipse Orbit.
The Orbit project is basically a repository of libraries to make them available for Eclipse Plug-in Development. What is especially nice in the Orbit libraries is that they also provide the sources. Thus, it is possible to view the implementation and get proper JavaDoc and so on.
Example
One can find the com.google.gson library using the update site
https://download.eclipse.org/tools/orbit/downloads/drops/R20190602212107/repository
Thereby, the part R20190602212107 refers to the Orbit build name that you find on the downloads page of the project.