You can also access databases from the classpath or from a jar file (in the classpath or not) as read-only databases.

You can create in-memory databases for use in testing and development and for processing temporary or reproducible data. See Using in-memory databases for details.

• Accessing databases from the classpath
  In most cases, you access databases from the file system. However, it is also possible to access databases from the classpath. The databases can be archived into a jar or zip file or left as is.
• Accessing databases from a jar or zip file
  It is possible to access databases from a jar file. The jar file does not have to be on the classpath.