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Pre-populate local Maven cache with specific dependencies

It looks like mvn install:install-file is for downloading a jar to a specific location.
I just want to manually download some publicly accessible dependencies to my local Maven cache (specifically the help and versions plugin). It doesn't have to be specific versions, just the latest versions is fine
I want Maven to install them just like it would with the install goal but just execute this from command line without a pom. Is this possible?

If you don't want create a pom.xml then you can use download-maven-plugin's artifact goal as shown in the below example.
You need pass groupId, artifactId and version. It
can't download the file if any one of these 3 are missing or not
matching with central repo. If you don't want to download pom file, you can ignore the second line.
Example:
mvn com.googlecode.maven-download-plugin:download-maven-plugin:1.4.2:artifact -DgroupId=log4j -DartifactId=log4j -Dversion=1.2.4 -Dtype=jar -DoutputDirectory=C:\Temp
mvn com.googlecode.maven-download-plugin:download-maven-plugin:1.4.2:artifact -DgroupId=log4j -DartifactId=log4j -Dversion=1.2.4 -Dtype=pom -DoutputDirectory=C:\Temp
This will download both JAR and POM files for log4j:log4j:1.2.4 from central repository to your local repository and also copies the files to C:\Temp folder. Once you are done downloading all the files, you can delete the Temp folder.

maven: how to specify "systemPath" for dependencied installed locally?

I've got one myPackage maven project, compiled and installed to local maven repository under
~/.m2/repository/mygroup/myPackage/1.0-SNAPSHOT/myPackage-1.0-SNAPSHOT.jar
In another maven project, I wish to use it, and in pom.xml I write <dependency> section for it. But I don't know how to write the "systemPath" for this jar:
I cannot use "~" to specify the path, because "~" is a *nix shell extention, java/maven cannot recognize it.
I cannot hard code like
/home/myself/.m2/...
It's not portable.
I cannot use ${project.basedir} because these 2 maven projects are under different folders. But I guess there should be some other maven environment variables that could indicate "home directory"?
All I wish to do is to get this "systemPath" done.
---------------Problem solved by using another project as dependency------------
<systemPath>${project.basedir}/../myPackage/pom.xml</systemPath>
That works!

A system path is required when the library that your project depends on is not in the maven local repository.
As a rule of thumb, this approach is indeed not portable at all and should be avoided for real projects.
Now, the dependency is in local repository if:
It was downloaded from some remote repository (usually)
You've installed it locally (in this case its in your local repository but might not be in your team-mate repo)
In order to install the dependency into the local repo consider using: mvn install:install-file+ parameters as written here
But from your question, it looks like the file is already there... Anyway once the file is in the local repository you can just define a "regular" dependency (group, artifact, version) and Maven will pick it, no need to fiddle with system Path in this case.

Maven deploy:deploy-file removes extension from file

I am trying to deploy signature files separately using deploy-file goal to Nexus staging repository, but I noticed that mvn deploy plugin removes the extension. My file is something like: azerty-0.1.jar.asc
but the file that gets deployed is: azerty-0.1.asc
I tried adding a classifier: -Dclassifier=jar
the file that gets deployed is: azerty-0.1-jar.asc
This seems like a strange behaviour.
Question: Any ideas how to work around it?

This is rather a normal behavior, Maven is using the file extension as artefact packaging, from maven-deploy-plugin, deploy-file, packaging option:
Type of the artifact to be deployed. Retrieved from the <packaging> element of the POM file if a POM file specified. Defaults to the file extension if it is not specified via command line or POM.
Note: bold is mine.
Moreover, the classifier option would indeed add an - between the version and the string provided as classifier: that's maven convention.
In your case you want to specify a special packaging, which would be jar.asc if you really want the remote file to have as extension jar.asc.
The following would hence work:
mvn deploy:deploy-file -Dfile=azerty-0.1.jar.asc -Dpackaging=jar.asc -DrepositoryId=your_id -Durl=http://your_repository -DgroupId=your_groupId -DartifactId=azerty -Dversion=0.1
Note the -Dpackaging=jar.asc which effectively tells Maven the file extension would be jar.asc.
As a general note, if you are using the repository as a build store, that would still be reasonable, otherwise in your case you would push to a Maven repository an artifact which would then be difficult (or rather weird) to import in a project.
If instead this is really an additional artifact of your project, you should look at the attach-artifact goal of the build-helper-maven-plugin, to effective define it as additional artifact, then Maven will automatically add it to its install and deploy phase.

Maven dependency issue - artifact not found in central repo

I'm trying to build the project from this site http://www.joptimizer.com/usage.html. I downloaded the sources jar file, unpacked it and ran maven package in the root folder. Maven fails at the last minute saying it couldn't resolve the dependency..
could not find artifact seventytwomiles:architecture-rules:jar:3.0.0-M1 in central repo - repo.maven.apache.org/maven2 ..
I have a feeling I might need to change something in the pom.xml file for this to work, but have no idea what. Googling for this missing dependency lead me no where. In general, how would one know what to do to handle such errors (and also please help with this specific case).

Specifically
According to the Building notes on http://www.joptimizer.com/usage.html:
JOptimizer is build on maven 3.0. Before building it, you must resolve
(in pom.xml) the external dependency on Colt and other dependencies
that aren't in public repositories. Please refer to the "Dependencies"
report for a complete treatment. For ease of use a boundle with
these external libraries is provided (visit "Download"): extract the
boundle in a folder and run the "maven-install.cmd" (translate it in
your own shell language), and you will get the artifacts in your local
repository.
To get the bundle for this, go to http://sourceforge.net/projects/cvxopt/files/, and download the appropriate version of joptimizer-3.X.X-dependencies.zip. Unzip in your own folder, and run mvn install:install-file -DgroupId=seventytwomiles -DartifactId=architecture-rules -Dversion=3.0.0-M1 -Dpackaging=jar -Dfile=architecture-rules-3.0.0-M1.jar -DpomFile=architecture-rules-3.0.0-M1.pom
Generally
Use a tool like http://mavenrepository.com to search for another version of the missing dependency and update your POM with the proper version. If MVNRepository doesn't know about it, you can install the dependency yourself. If you are working with a group of developers, as Eric Jablow mentions, an artifact repository like Nexus or Artifactory is great for sharing non-public dependencies. If it's just you, you can install the artifact in your local repo as described here: How to manually install an artifact in Maven 2?

You should add your own repository manager like Nexus or Artifactory. Then, find out where this dependency is kept; there are repositories other than central. If it's kept on another repository, have your repository mirror that too.
Otherwise, Nexus or Artifactory have commands to enter the dependency manually. Create a local repository called "Third-party" and add it there.
Finally, change your settings.xml file to refer everything to your repository manager.
The most common case for this is when a company refuses to license their products to be held at the central repository. For example, Microsoft won't let its sqljdbc.jar file be distributed through Central. So, you need to add it by hand.

Change the dependency as follows
<dependency>
<groupId>org.architecturerules</groupId>
<artifactId>architecture-rules</artifactId>
<version>3.0.0-rc1</version>
<scope>test</scope>
</dependency>
Add the repository in pom
<repositories>
<repository>
<id>architecturerules.googlecode.com</id>
<url>http://architecturerules.googlecode.com/svn/maven2/</url>
</repository>
</repositories>

Configure Maven To Create An Archive File With All Dependencies Defined in POM XML

I am working in a private network which doesn't have internet proxy.
I can not create a local repository as well which involves the bureaucracy, management won't allow it. I may be a long term fix but not the solution for the question I asked.
I can not keep maven as a build tool as it requires the direct or indirect internet connection.
I HAVE to use ANT for building the project hence using maven in offline mode also not an option for me.
But I still want to use the maven dependency management for collecting all the jars in a one archive smartly.
My plan is to generate a ZIP file containing dependencies resolved using maven. And then we will share this ZIP file to all developers working inside a private network which doesn't have internet connection.
To do so I will get a temporary access to a computer which is having internet connection and from there I will define a dummy POM with all the dependencies required.
Now the question is how do I generate a ZIP file ( not a single jar ) using maven which contains all the dependencies defined in POM.

while what youre suggesting is technically possible, it is (in my opinion) not the best solution to your problem.
your statement that
it requires the direct or indirect internet connection
is not accurate. what maven requires is a maven repository (or a set of them) to fetch stuff from. the best solution to your problem would be to install a local maven repository inside your organization's network. the 2 most popular choices for a loaclly-run maven repository seem to be nexus and artifactory - both offer free open source versions and paid supported pro versions.
once you set up a maven repository inside your organization's network and populate it with the artifacts you require you can simply configure all of your project's pom files to go to those repositories. for example, to configure maven to use your repo instead of maven central, you can do this:
<repositories>
<!-- override central -->
<repository>
<id>central</id>
<url>http://your.repo.location</url>
</repository>
</repositories>
you will need to map a plugin repository in a similar fashion.
its also possible to achieve this by configuring the maven settings.xml file in each user's home directory if you dont want this in the pom files but from my experience its less error-prone this way

use following command to build Maven project offline.
mvn -o package
Refer this and this for more information.

I ended up with a smart hack which lets me do dependency resolution and archiving!
I am creating a dummy maven web project with all the dependencies defined in pom xml.
Now the war packaging mode is used by default for web applications.
I simply install the maven project from internet facing machine.
I get all the dependencies and transitive dependencies in war file's "lib" directory with dependency naming version remaining unchanged !!!!
Copying and adding those files into an ANT project is a trivial task then..!