Spring Boot Native - Can't find file in /resources

Question

I've built a Spring Boot native executable using the command mvn clean package -Pnative but it can't read files in /resources.

Java code:

        try (InputStream inputStream = Reader.class.getClassLoader()
                                                   .getResourceAsStream(filename)) {
            if (inputStream == null) throw new RTException("Can't find file " + filename + " in /resources.");
            fileString = IOUtils.toString(inputStream, UTF_8);
        } catch (Exception e) {
            throw new RTException("Issue reading or parsing file " + filename + "\n" + e.getMessage());
        }

In pom.xml, as required in this Baeldung article:

        <profile>
            <id>native</id>
            <build>
                <plugins>
                    <plugin>
                        <groupId>org.graalvm.buildtools</groupId>
                        <artifactId>native-maven-plugin</artifactId>
                        <executions>
                            <execution>
                                <id>build-native</id>
                                <goals>
                                    <goal>compile-no-fork</goal>
                                </goals>
                                <phase>package</phase>
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In META-INF/native-image/[groupId]/[artifactId]/native-image.properties:

Args = -H:IncludeResources=".*/*.txt$"

When launching the native executable, I get

(...).RTException: Issue reading or parsing file file.txt
Can't find file file.txt in /resources.`

The file file.txt is in /resources and there is no problem reading it using a non-native build.

What am I missing here ?

Answer 1

Found it.

Adding native-image.properties under META-INF only works when running the command native-image -jar [app.jar] (not tested though).

When building the native image with Maven, it doesn't read the content of META-INF (tested with some invalid arg in native-image.properties, no error thrown).

To make it work I've added <buildArgs> this in the Maven plugin config (found in plugin doc):

               <plugin>
                   <groupId>org.graalvm.buildtools</groupId>
                   <artifactId>native-maven-plugin</artifactId>
                   <executions>
                       <execution>
                           <id>build-native</id>
                           (...)
                           <configuration>
                               <buildArgs>-H:IncludeResources=.*txt$</buildArgs>
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