For a Maven-driven project in IntelliJ 2018, when should I choose to use…
The IntelliJ 2018.1 menu item Build > Rebuild Project
The Maven panel’s clean and install Lifecycle items
Under what circumstances is either appropriate?
My situation is a Vaadin 8 application using the vaadin-archetype-application-multimodule Vaadin archetype.
The Question, Does IntelliJ Build > Rebuild Project invoke maven? has a single Answer that says the Rebuild Project does not invoke Maven at all. But no guidance is given on when to use route versus the other.
Well, if you make substancial changes within a pom.xml file (new plugins, new modules within a multi-module project), you'd better run "mvn clean install". I personally never use the "Rebuild Project" within a Maven project. usually I just "make" the project so the class files are updated, or I start a real Maven build to get new / updated dependencies.
The third important option (for me) is the "Reimport all Maven projects" option, which is quite useful if a pure Maven build runs fine, but IntelliJ still thinks that there is something wrong within your project.
When you have a multi-module Maven project and:
Start your tests and application programmatically by IntelliJ (Main.java):
You do not need to use Maven at all, no clean, no install, only Make. And Rebuild when the project gets screwed up.
Click Reimport when you change dependencies or someone deploys a new dependency snapshot to your repo.
If IntelliJ refuses to download the snapshot, then try mvn clean install.
And why would you even do all that? It is faster and more user friendly.
Start your tests and application by Maven in IntelliJ (mvn jetty:run):
You have to install your modules which are as dependencies for the module on which you start your application (mvn jetty:run), because Maven does not use your compiled output for dependencies, but takes an artifact from your remote/local repository. For this case Make/Rebuild is useless, you have to use mvn (clean) install.
If you have made changes only in a module on which you run mvn jetty:run then you do not need to use package/install, but sometimes you have to use clean or Rebuild as Maven does not remove deleted resources.
Make is good for hot-swap - for that reason, it is a good idea to import all Maven projects you develop and on which you depend into a single IntelliJ project. Initial Rebuild comes handy, because without it, Make would compile the whole project instead of only changed classes, then possibly failing hot-swap or it would just take too long.
Or you could just click Make before you run your application, but it could leave some old resources created by Maven in compiled output, Rebuild would take care of that.
You can also configure your app-server to restart/reload when it detects updated files from Make or Rebuild - certainly faster than restarting the JVM or compiling by Maven, but you might like to disable that and use only hot-swap, which is still way faster if you do small changes.
Either way you might want to take a look at Maven Helper plugin for IntelliJ, it will make things way easier in big projects.
Related
I inherited a multi-module Maven project that had been maintained using Eclipse, and now I really want to use VSCode instead.
It seems the VSCode best practice (based on this video) is to run mvn war:exploded and then right-click target/classes to launch each of the modules into Tomcat.
This is very laborious for a project with several modules, and also time-consuming considering I need to run mvn package before mvn war:exploded every time the code is changed.
Is there a way to setup VSCode to remove some or all of the recurring manual steps, and provide an experience that feels more like incremental compile & hot-deploy?
Since I'm having performance issues while building a workspace with lots of maven-projects I wonder if it is possible to deactivate the Maven Project Builder.
If I understand that right, the Maven Project Builder does not compile anything. Instead it refreshes the project-config from the POMs. I believe this is exactly what happens if I run "Maven -> update Project". If that is true I could deaktivate the Project Builder... Does anybody know if this is right?
You need to track all your library dependencies from .m2 folder, so you can restore them easily, and check if there are some scripts in pom.xml that run on build, test, or deployment and see if you can reproduce them without Maven.
In addition you should check if there are other project in your system that depends on your project and vice versa via Maven.
I couldn't really find an answer anywhere to this particular question.
I have a (Maven) project consisting of multiple modules, let's say a core module (a jar) and a webapp module (a war).
When I run mvn clean package on my webapp, does it automatically always build the core first and will it pick up any changes in it? Do I have to run mvn clean install instead? Or do I have to run mvn clean package/install on my parent pom?
Does it matter if the parent/module is a release or a snapshot?
If you are working with a so called Multi Module Build you should do everything what you like to do with your whole project from the parent level.
There you can do:
mvn clean package
than it will build all modules in the correct order (assuming you have defined the dependencies between them correct).
If you have such a multi module build all your modules incl. your parent should have the same version number. If you like to make a release of the whole you can simply start from the parent.
You have to build anything that's changed, upwards. So, if you change core, then rebuild core, then rebuild your war. If you've just changed your war, then you only need to rebuild your war. Cleaning is generally good practice. The reason not to do it would be if you're generating a bunch of entity classes, which takes a long time to redo.
I've seen a lot of mistakes because people forget to clean, and then some old piece of code is still active, even though they thought they'd deleted it.
Installing will put your latest build into your M2 repo, which is generally a good idea too. You really can't go wrong with "mvn clean install"
This feels like a really stupid question but I haven't been able to find an answer.
I'm working on a maven project but I do most of my development in eclipse. Is there any way for me to force maven to generate all of my dependencies under target even if there are errors in the code? I set my eclipse project's build path to use the jars under target/dependencies/jars, but calling mvn clean kills them and if there are any errors in my code causing it to not compile mvn package won't create the dependencies but will instead just crash saying BUILD FAILURE. This makes the problem even worse since instead of seeing the actual errors my eclipse will just bombard me with errors everywhere since all of its dependencies just died.
Or maybe the way I'm working with it is just stupid and there's a better way.
Are you using the m2e plugins for Eclipse to process maven projects, or simply importing the projects as general ones?
If the latter, you should use the m2 plugins (simply go to the Eclipse Marketplace and search for Maven), as they interrogate your POM and set up your dependences properly. You can then concentrate on any compile errors in your code.
You should not point to the jars in the target folder for dependent JAR's since this is where the products of building your project are stored. Performing a mvn clean removes this folder.
To use Maven with Eclipse install the m2e plugin in Eclipse. This makes Eclipse understand the structure of Maven projects.
Once installed you can import your Maven project into Eclipse. I use Import... | Existing Maven Projects for this. But you can also directly import form a versioning system.
During the import Eclipse will set up the Eclipse project to use the Maven dependencies to locate the required JAR's. These are taken from the repository as configured with the used Maven installation.
I found an annoying issue working with m2eclipse in Eclipse.
My workspace contains 2 projects, an application A and a library B. The application A POM has B as a dependency and everything works correctly. (The project dependecy is found and used when I build the application)
But if I change some code in project B and I forgot to mvn:install it, when I build the application it uses the last built version of the library and it loses my last changes.
Is there a way to force Maven / M2Eclipse to check if the source code of the dependecy is newer than the last version built, and to install it when installing/ deploying the main application?
Or maybe my approach is wrong or is something obvious that I'm missing?
You can tell m2eclipse to use resolve dependencies from the workspace rather than through the normal mechanisms. In your project properties (NOT workspace properties), select Maven->Resolve dependencies from Workspace projects.
This will mean that when you change B and subsequently build A, the changes should be picked up automatically.
If, however, you build outside Eclipse, you'll have to do the normal mvn install to get the correct dependencies.
I don't know of a way to tell maven to build the library first, then build your project. You could put two maven commands into a script and run the script.
Alternatively, you could put both projects inside a maven parent project, and then build the parent. This causes all child project to be built too (so in your case the library, and the application).
I think you have couple of options here
If you can change the maven project set up, I would suggest you to use maven multimodule
Option two might solve your problem but still involves a manual stop when you change your dependent project B, Do this on for your dependent project in eclipse
Select Library B ==> Properties ==> Maven ==> in the input box under Goals to invoke after project clean: ==> enter : install
To deploy any change that you made to Project B in eclipse to maven local/remote repo, You have to run Clean build in eclipse, This will deploy the latest Library B to the maven repository
Also make sure your Library B version is a SnapShot during the development
If you are looking to run the latest snapshots on your local machine you should try to set things up to launch directly from Eclipse.
Apart from avoiding the problem you originally posted about, it also has other advantages.
It will save you a lot of time by not having to perform intermediate build steps.
You can start and stop servers without having to leave your IDE.
The Eclipse console has extra features that you don't get from the system console.
You don't have to modify your start scripts to attach a debugger.