The program cvrdecode will store data from a collection of California
digital vaccine records in a file or print it to standard output.

With no arguments a simple GUI will walk the user through the process
of generating the output file.  The GUI shows a table of buttons. The
first two set an input directory and the output file. When one of
these is set, the corresponding button changes color (to a pale
yellow).  Both must be set to continue.  The 'Run' button will then be
enabled so the output can be generated.  Before exiting, the user can
click on a button to display a console (for error messages) or a
button to display the table that was created. An "Exit" button
terminates the program.

Otherwise, cvrdecode works as a command-line program. The options are
described in a manual page (cvrdecode.1).

To compile, just type the command

  make

and to create a Debian package, type the command

  make deb

The file CaVaxRecDecoder.java contains comments outlining how to
verify a digital signature and where to find some of the documentation
(the specifications one will initially find in a Google search are
lacking with regard to citations and some important details are
assumed to be obvious, so it takes some time to generate a clear
description of what to actually do).

The Debian packages needed for compiling are:

    openjdk-11-jdk           (or later)
    openjdk-11-jdk-headless  (or later)
    openjdk-11-jre           (or later
    openjdk-11-jre-headless  (or later)
    inkscape-1.0.2-3ubuntu1  (version 1.0.2 or later)
    libbzdev-java (see <https://billzaumen.github.io/bzdev/>)
    libjcommander-java  (for a package dependency but not used)
    libzxing-java
    libzxing-core-java
    libzxing-javase-java

The Debian packages needed for running are:

    openjdk-11-jdk           (or later)
    openjdk-11-jdk-headless  (or later)
    openjdk-11-jre           (or later
    openjdk-11-jre-headless  (or later)
    libbzdev-java (see <https://billzaumen.github.io/bzdev/>)
    libjcommander-java  (for a package dependency but not used)
    libzxing-java
    libzxing-core-java
    libzxing-javase-java

The program inkscape is used to generate icons of various sizes.
The icon is in cvrdecode.svg and inkscape can convert that to PNG
files of various sizes. The libzxing packages have a dependency on
the package libjcommander-java.  The jar file from
libjcommander-java does not appear to be needed at compile time or
run time given the zxing classes cvrdecode uses.

Two jar files provided by libbzdev-java are needed:

    libbzdev-base.jar  (for generating CSV files and parsing JSON)
    libbzdev-desktop.jar (for a GUI component for tables)

Two jar files provided by the libzxing packages are needed:

    core.jar   (QR code processing)
    javase.jar (QR code processing)

The module org.bzdev.desktop is dependent on the modules
org.bzdev.base and org.bzdev.graphics, which in turn is dependent on
org.bzdev.math and org.bzdev.obnaming, but the GUI component from
org.bzdev.desktop that is used by cvrdecode does not use any classes
from these additional modules.  As a result, cvrdecode does not use
Java modules - primarily to keep the number of jar files needed to a
minimum.

To create a Debian package, the usual dpkg tools are needed including
the fakeroot program from the package fakeroot.