maven when to use clean over compile - maven

When running mvn clean install
It will clean target directory, compile and run tests.
However it does not run any of the clean options unless its explicitly stated? e.g. this will not clean the target directory
mvn install
So I often run clean just to be sure its always fresh.
If I make a code change do I need to always clean if wanting to verify the new code changes?.
compile is part of the default life cycle which runs when I type mvn install doesnt this do the same thing? Whats the main benefit of clean?

The clean goal removes any of the output files located in target/ or wherever else you've specified them.
Incremental compilation is a thing in Maven - which is why other goals don't automatically assume clean - but it is often considered to be unreliable at best. For sanity's sake, it is best to always clean your workspace so that you don't get bizarre class collisions.

clean command clean your target (your projects build location).
install command build your package and put it into your maven local repository also thats why other project can use your projects as library from maven local repository.
and compile just compile the source code of the project.
So If you use mvn clean install it will first clean your build directory then compile your project and build target directory with compiled files and then put it into your maven local repository. So you can use your projects files to others project from your maven local repository.
and mvn clean compile will first clean your build directory and then compile your project and build target directory with compiled files

Related

Can you modify files in a repository right after issuing maven compile install?

For projects which take a long time to build, can you issue the maven compile or maven install commands and then continue making changes to the files in your repository, without these changes affecting the outcome of the maven install command?
Is a snapshot automatically taken when the command is issued? If not, is there a way to request that maven take a snapshot of the project when a command is issued, so that you could continue making changes after that snapshot?
If you build locally, you should not be changing files while you build because you might break the build.
If you build on a build server, it depends:
If you run a clean package or clean install, then there is just one checkout at the beginning. After that it should not be a problem to make further commits.
If you build a release with Maven release plugin, you should probably be more careful. I haven't actually seen any problems in nature yet, but since the Maven release plugin commits to git/svn itself, you might cause problems when committing during the build on the same branch.

Download all transitive dependencies on mvn install

I'm currently starting to get into Maven.
I've been tasked to create a maven environment for a large pre-existing project and I want the build environment to be as portable as possible. My problem is, that on a machine with a fresh maven installation, my project does not seem to download transitive dependencies when in run 'mvn install'.
Currently maven comes up with a build order like this:
ProjA
ProjB
Project A has some dependencies and code that Project B depends on. So I set Project B to only depend on Project A. When running 'mvn install' though, compilation of ProjB fails, because it says it is missing a package that ProjA depends on.
Am I running the wrong command for a fresh setup, or do I have to add a specific line in the POM of Project B to make it work on a fresh machine?
Thanks in advance.

What is the difference between "mvn clean install" & "mvn eclipse:clean eclipse:eclipse" command?

I have a maven project in eclipse. I use mvn clean install for installing dependencies in pom.xml.
I want to know what mvn eclipse:clean eclipse:eclipse command does and also the difference between these two?
mvn eclipse:clean eclipse:eclipse
The second command is completely different from the first one.
First, it deletes previously generated Eclipse files (like .project and .classpath and .settings) and then generates new ones, thus, effectively updating them. It may be useful if you introduced some changes in pom.xml (like new dependencies or plugins) and want Eclipse to be aware of them.
mvn clean install
The first command deletes target directory and then builds all you code and installs artifacts into local repository.

Maven re-build and deploy

I'm new to compiled web development, and I'm just trying to figure out the build/deploy process.... I've done:
mvn clean install
on a project, which built and deployed the project and now I can see it. If I want to make changes to the codebase, do I really need to run mvn clean install again to re-build and deploy the changes or is there a way to do a quicker build without using a "proper" IDE?
I'm using vim/gvim
Thanks!
Maven already handles the dependencies and only re-builds the necessary files... unless you throw away all previous build artifacts with clean! You should only need to use clean when you run into problems, or when you have checked out a different version from version control. Usually, mvn install should suffice.
You can integrate that with Vim; the simplest is to
:set makeprg=mvn
and then trigger a build with :make install.
Plugins build on that simplistic setup, e.g. check out:
maven-plugin
maven-ide

How to deploy own files from maven

I am installing and running sakai project from command prompt
mvn install sakai:deploy
but command prompt show me error that 2 artifact missing that is 2 jar files are missing dwnload it manually
i am dwnload it and save it in local system then how i can install and deploy it
When you build Sakai it will generate that missing jar file and place it into the local maven repo. That said, this version of Sakai is very old and you should be running Sakai 10. We suggest you upgrade to Sakai 10 and maven 3. If you do, this issue will go away.
The process for building Sakai is as follows:
Open a command line shell
Change directory to your Sakai source root directory (should contain many directories including the "master" directory)
Execute mvn clean install to build the Sakai source using maven
Note: The build will take an extra 5-10 minutes to download dependencies the first time
Execute mvn sakai:deploy to deploy Sakai to your tomcat using maven
Partial builds are supported by the maven2/3 build system
You can do a "mvn clean install sakai:deploy" from any subdirectory and build just that code
Once you have downloaded the jars you can run maven off-line with mvn -o clean install sakai:deploy
As i can understand you have to manually add the jar in .m2 repository where it needs to be or
add dependency in pom.xml for it(it will automatically add it in repository).
One more thing you can try, go to project>right click>build path> add external jar (it will add the jar to your project).

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