Central Maven Repository Publish Experience

This week I published an Open Source Project that I maintain, to the Sonatype OSS Repository Hosting Service, with the objective of make the project available in the Central Maven Repository.

The project that I published is the FFPOJO Project, which is a Flat-File Parser, POJO based, library for Java applications.

The objective of this post is to comment my experience in the publishing process and provide some tips and points to people who are in this process to.

• It’s quite obvious but you must own the domain in your GroupId and the package names must start with this domain too;
• If you host your project at GitHub, you can create a free account and turn it on an organizational account, then link this account to your personal user as an organization member. This can provide you an domain like “https://github.com/projectname”, which let you to use the group id and package names like “com.github.projectname”;
• Create a parent-pom and use inheritance and multi-modules to concentrate project-specific pom tags into the parent-pom and facilitate the release process. Remember that the nested project structure is more compatible than flat structure;
• Follow strictly the instructions in the official Sonatype repository usage guide;
• Use the javadoc pluging and the source plugin to generate the “-javadoc.jar” and “-sources.jar”;
• Use the maven release plugin to facilitate the release management;
• If you use GitHub and Windows for development, you might get an error on release:prepare that maven stucks after the push command. This happens when you use passphrase in your GitHub SSH certificate. The best solution I found is to use other certificate with no passphrase. I found other solutions like use putty pageant/plink to cache the certificate and passphrase and use it as ssh client, but not worked for me. The easiest is not use passphrase at all;
• If you use GitHub and Windows for development, when you call release:prepare on Cygwin Git Bash, you might see an error like “pom.xml is outside repository”. It’s a relative/absolute path trouble in the maven git scm plugin. The best solution I found is to run maven from cmd.exe instead of Git Bash. Then the ssh.exe and git.exe folders must be in the PATH variable;
• Don’t forget to publish your GPG public key at the public keyservers (hkp://pool.sks-keyservers.net, hkp://keyserver.ubuntu.com, hkp://pgp.mit.edu). This is verified by the central at release promotion time.

That’s it. I have not found any other trouble in the process, it is very fast and the JIRA administrators are very attentive. Finally, the FFPOJO framework can be found in the Maven Central like any other open source framework:

<dependencies>
	<dependency>
		<groupId>com.github.ffpojo</groupId>
		<artifactId>ffpojo</artifactId>
		<version>1.0</version>
	</dependency>
</dependencies> 

If you want to know better the FFPOJO library, please visit the project website on GitHub.

Gilberto Holms