Understanding Dependency - Starting HSQLDB server from Maven

Dependency is a mechanism for controlling modules in a project. Each dependency needs to be added under the dependencies element in pom.xml.

A dependeccy needs at least those elements: groupId, artifactId and version. To have mvn starting the HSQLDB server as specified in the tutorial, we need to add a dependency refering to an installed version of HSQLDB on the local drive. For that purpose, we need to know the groupId, the artifactId to be used. Using Google, ibiblio can help you know the correct groupId and artifactId to use for HSQLDB. In Google, search for "http://www.ibiblio.org/ maven2 hsqldb".
Open maven2-metadata.xml; this file contains the information about the groupId and artifactId for HSQLDB which are for both hsqldb. You also need to specify the scope element.
Maven Guide defines the scope of the dependency as a property that limits dependency transitivity. When you run Maven, it needs to discover the libraries needed for your application. Maven uses the dependency defined in pom.xml, but sometimes those dependencies require other dependencies that Maven will discover and include them automatically.
As specified earlier, the scope limits the transitivity of a dependency. There are 6 scopes that can be used, and the one to use when using a jar file from your local system (hsqldb is actually a jar file) is system.
The dependency element to add in your pom.xml is going to be:
<dependency>
<groupeId>hsqldb</groupId>
<artifactId>hsqldb</artifactId>
<version>2.0.0</version>
<scope>system</scope>
<systemPath>path/to/hsqldb.jar</systemPath>
</dependency>

You need to download hsqldb and add \lib to your system Path environment variable (user environment variable for Linux should work).
Then from the command line, type: mvn exec:java
-Dexec.mainClass="org.hsqldb.server.Server" -Dexec.args="-database.0 file:target/data/tutorial"