Yes, we can use the UCanAccess JDBC driver to connect to Access databases (.mdb and .accdb) in LibreOffice Base. Here's how I did it on a clean install of Ubuntu 14.04 LTS.
Important Note: These instructions apply to UCanAccess version 3.0.5 and later (including version 4.x). Before proceeding, verify that you are using the latest version of UCanAccess, available here.
One-Time Setup
First, I installed LibreOffice Base
sudo apt-get install libreoffice-base
Then I downloaded UCanAccess (bin.zip
file) and unzipped it into the folder
~/Downloads/JDBC/UCanAccess

Note: When unzipping the distribution file be sure to specify "Keep directory structure" (or similar, depending on your unzip tool) so the folder structure appears as in the screenshot above.
I launched LibreOffice (not Base, just LibreOffice itself)

and chose Tools > Options

On the Advanced tab I clicked the "Class Path..." button

and then added the following JAR file using the "Add Archive..." button:
/home/gord/Downloads/JDBC/UCanAccess/loader/ucanload.jar

Note that this is ucanload.jar in the loader/ subfolder, not "ucanaccess-x.y.z.jar” in the UCanAccess home folder.
Important: You must close and re-open all LibreOffice (or OpenOffice.org) components for the new "Class Path...” value to take effect. That includes any "quick start” features or other related processes. (If you want to play it safe, simply restart your machine.)
Per-Database Setup
I launched LibreOffice Base, and in Step 1 of the wizard I chose "Connect to an existing database (JDBC)"

The Access file I wanted to manipulate was named "uca301demo.accdb" in my Documents folder, so in Step 2 the "Datasource URL" was
jdbc:ucanaccess:///home/gord/Documents/uca301demo.accdb
and the "JDBC driver class" was
net.ucanaccess.jdbc.UcanloadDriver

In Step 3, I left the "User name" field empty and just clicked "Next >>".
In Step 4, I saved the LibreOffice Base database as "accdbTest.odb" in my Documents folder.
When the wizard completed it opened my LibreOffice database and I could see the tables and saved queries in the .accdb file
