Demo how to create JavaFX app with custom runtime image using SPI drivers such as JDBC drivers

The only purpose of this project is to investigate, how to properly configure a JavaFX project using Maven and the JavaFX Maven plugin. The interesting point is, how to properly link JDBC drivers in a customized runtime?

Boundary conditions

• JavaFX 15
• modular project, so all classes moved to module path
• Maven as build tool
• Javafx-maven-plugin
• Uses some SPI modules from: Microsoft SqlServer JDBC driver, MariaDB JDBC driver and PostgreSQL JDBC driver

Problem

When running the POM.XML without explicit configuration of --module-path in javafx-maven-plugin, the JDBC drivers are not found when running the image built using mvn javafx:jlink. On the other hand when executing mvn javafx:run, everything works as expected, the JDBC drivers are detected.

Doesnt work as expected when using mvn javafx:jlink:

<plugin>
	<groupId>org.openjfx</groupId>
	<artifactId>javafx-maven-plugin</artifactId>
	<version>0.0.5</version>
	<configuration>
	<stripDebug>true</stripDebug>
	<compress>2</compress>
	<noHeaderFiles>true</noHeaderFiles>
	<noManPages>true</noManPages>
	<launcher>demoapp</launcher>
	<jlinkImageName>hello</jlinkImageName>
	<jlinkZipName>hellozip</jlinkZipName>
	<mainClass>net.raumzeitfalle.demoapp/playground.javafx.ModularSpiDemo</mainClass>
	<runtimePathOption>MODULEPATH</runtimePathOption>
	</configuration>
</plugin>

Works! Yay!

As a workaround, one can use the maven-dependency-plugin to copy all dependencies to a certain location. So when before JLink is called, a copy task is executed and later Jlink can use the specified directory as module path.

<plugin>
	<groupId>org.openjfx</groupId>
	<artifactId>javafx-maven-plugin</artifactId>
	<version>0.0.5</version>
	<configuration>
		<stripDebug>true</stripDebug>
		<compress>2</compress>
		<noHeaderFiles>true</noHeaderFiles>
		<noManPages>true</noManPages>
		<launcher>demoapp</launcher>
		<jlinkImageName>hello</jlinkImageName>
		<jlinkZipName>hellozip</jlinkZipName>
		<mainClass>net.raumzeitfalle.demoapp/playground.javafx.ModularSpiDemo</mainClass>
		<runtimePathOption>MODULEPATH</runtimePathOption>
		<options>
			<option>--module-path</option>
			<option>${project.build.directory}/modulepath</option>
		</options>
	</configuration>
</plugin>

<plugin>
	<groupId>org.apache.maven.plugins</groupId>
	<artifactId>maven-dependency-plugin</artifactId>
	<version>3.1.2</version>
	<executions>
		<execution>
			<id>copy-dependencies</id>
				<phase>prepare-package</phase>
			<goals>
				<goal>copy-dependencies</goal>
			</goals>
			<configuration>
				<outputDirectory>${project.build.directory}/modulepath</outputDirectory>
				<overWriteReleases>false</overWriteReleases>
				<overWriteSnapshots>false</overWriteSnapshots>
				<overWriteIfNewer>true</overWriteIfNewer>
			</configuration>
		</execution>
	</executions>
</plugin>

How to run the project

> mvn javafx:run

How to create a runtime-image

The resulting runtime image won't be able to detect any JDBC drivers.

> mvn javafx:jlink

Alternatively, one could run the following line. The resulting runtime image will detect the JDBC drivers.

> mvn package javafx:jlink

Well, somehoe this does not feel correct yet, but certainly I'll have to do more work to gain better understanding of what Maven does here. It becomes possibly helpful but definitively interesting, when running the Maven process with an increased verbosity.

> mvn -X package javafx:jlink

Executing the runtime-image

The runtime image can be started then using:

> target\ModularSpiDemo\bin\Demo.bat