Maven

1. What is the difference between Group ID and ArtifactID ?

groupId will identify your project uniquely across all projects, so we need to enforce a naming schema. It has to follow the package name rules, what means that has to be at least as a domain name you control, and you can create as many subgroups as you want. Look at More information about package names eg. org.apache.maven, org.apache.commons

A good way to determine the granularity of the groupId is to use the project structure. That is, if the current project is a multiple module project, it should append a new identifier to the parent's groupId.
eg. org.apache.maven, org.apache.maven.plugins, org.apache.maven.reporting

artifactId is the name of the jar without version. If you created it then you can choose whatever name you want with lowercase letters and no strange symbols. If it's a third party jar you have to take the name of the jar as it's distributed.

eg. maven, commons-math

version if you distribute it then you can choose any typical version with numbers and dots (1.0, 1.1, 1.0.1, ...). Don't use dates as they are usually associated with SNAPSHOT (nightly) builds. If it's a third party artifact, you have to use their version number whatever it is, and as strange as it can look.

eg. 2.0, 2.0.1, 1.3.1




Your convention seems to be reasonable. If I were searching for your framework in the Maven repo, I would look for awesome-inhouse-framework-x.y.jar in com.mycompany.awesomeinhouseframework group directory. And I would find it there according to your convention.

Two simple rules work for me:

• reverse-domain-packages for groupId (since such are quite unique) with all the constrains regarding java packages names
• project name as artifactId (keeping in mind that it should be jar-name friendly)

Difference between SnapShot and release version?

A snapshot version in Maven is one that has not been released.

The idea is that before a 1.0 release (or any other release) is done, there exists a 1.0-SNAPSHOT. That version is what might become 1.0. It's basically "1.0 under development". This might be close to a real 1.0 release, or pretty far (right after the 0.9 release, for example).

The difference between a "real" version and a snapshot version is that snapshots might get updates. That means that downloading 1.0-SNAPSHOT today might give a different file than downloading it yesterday or tomorrow.

Usually, snapshot dependencies should only exist during development and no released version (i.e. no non-snapshot) should have a dependency on a snapshot version.