What's mdub?

mdub (mw on the command line) is a mvn / mvnw wrapper. Not to be confused with the Maven Wrapper, mw uses the Maven Wrapper on projects where one is configured, and falls back to use the mvn from the $PATH if a wrapper is not available.

Installation

Installation with brew

TODO

Installing mdub from source

You will probably want to install Maven first. While this is not technically necessary if all your projects are using a Maven Wrapper, it is a good idea to have the latest version of mvn available system-wide because some handy Maven features are available outside the context of an existing project.

Check out a copy of the mdub repository. Then, either add the mdub bin directory to your $PATH, or run the provided install command with the location to the prefix in which you want to install mdub. The default prefix is /usr/local.

For example, to install mdub into /usr/local/bin:

git clone https://github.com/dansomething/mdub.git
cd mdub
./install

Note: you may need to run ./install with sudo if you do not have permission to write to the installation prefix.

Aliasing the mvn command

For maximum fidelity add a mvn alias to mw to your shell's configuration file.

Example bash:

echo "alias mvn=mw" >> ~/.bashrc
source ~/.bashrc

From now on you can just type mvn ... from wherever you are and mw takes care of the rest. Happiness ensues!

Why mdub?

The problems with mvn and mvnw

mdub is a convenience for developers running local Maven commands and addresses a few minor shortcomings of mvn and mvnw's commandline behaviour. These are known issues, and they are set to be addressed in future versions of Maven. If you are interested in the discussions surrounding them, check out:

Here are the issues I feel are most important, and the ones mdub attempts to address:

You have to provide a relative path to pom.xml

If you are using the mvn command, and you are not in the same directory as the pom.xml file you want to run, you have to provide mvn the path. Depending on where you happen to be, this can be somewhat cumbersome:

$ pwd
~/myProject/src/main/java/org/project
$ mvn -f ../../../../../pom.xml compile

With mw, this becomes:

$ mw build

You have to provide a relative path to mvnw

If you are using mvnw and you want to run your build, you need to do something similiar and provide the relative path to the mvnw script:

$ pwd
~/myProject/src/main/java/org/project/stuff
$ ../../../../../../mvnw compile

Again, with mw this becomes:

$ mw build

You have a combination of the above problems

I don't even want to type out an example of this, let alone do it on a day-to-day basis. Use your imagination.

Typing ./mvnw to run the maven wrapper is kind of inconvenient

Even with tab completion and sitting at the root of your project, you have to type at least ./mvn<tab>. It gets a bit worse if you happen to have a maven.properties file, and with the Maven wrapper, you have a mvn directory to contend with as well. A simple alias would solve this problem, but you still have the other (more annoying) issues to contend with.

You meant to use the project's mvnw, but typed mvn instead

This can be a problem if the project you are building has customizations to the Maven wrapper or for some reason is only compatible with a certain version of Maven that is configured in the wrapper. If you know the project uses Maven, you may be tempted to just use your own system's Maven binary. This might be ok, or it might cause the build to break, but if a project has a mvnw, it is a pretty safe bet you should use it, and not whatever Maven distribution you happen to have installed on your system.

The mw payoff

Anywhere you happen to be on your project, you can run the Maven tasks of your project by typing mw <tasks>, regardless of whether you use the Maven Wrapper in your project or not.

mw works by looking upwards from your current directory and will run the nearest pom.xml file with the nearest mvnw. If a mvnw cannot be found, it will run the nearest pom.xml with your system's Maven. This is probably always what you want to do if you are running Maven from within a project's tree that uses the Maven build system.