Remove native-image.properties from micrometer-core

[zakkak]

Please describe the feature request.

Remove -H:ReflectionConfigurationResources=${.}/reflect-config.json from native-image.properties file.
The option should not be necessary for native-image to pick up the reflect-config.json file, while with this option included native builds using GraalVM for JDK 21 print the following warning:

Warning: The option '-H:ReflectionConfigurationResources=META-INF/native-image/io.micrometer/micrometer-core/reflect-config.json' is experimental and must be enabled via '-H:+UnlockExperimentalVMOptions' in the future.

The option is passed in https://github.com/micrometer-metrics/micrometer/blob/3513df3780ab2fe1119ec2f9a6099ddcff7e7544/micrometer-core/src/main/resources/META-INF/native-image/io.micrometer/micrometer-core/native-image.properties#L17C8-L17C68

Rationale
As noted in the warning the use of '-H:ReflectionConfigurationResources=` is experimental and should thus be avoided.

Additional context

Reproducer:

wget https://github.com/graalvm/graalvm-ce-builds/releases/download/jdk-21.0.0/graalvm-community-jdk-21.0.0_linux-x64_bin.tar.gz
wget https://repo1.maven.org/maven2/io/micrometer/micrometer-core/1.11.5/micrometer-core-1.11.5.jar
tar xf graalvm-community-jdk-21.0.0_linux-x64_bin.tar.gz
cat > Main.java <<EOF                                                                                                                                                                     
public class Main {
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}
EOF
./graalvm-community-openjdk-21+35.1/bin/javac Main.java
./graalvm-community-openjdk-21+35.1/bin/native-image -cp ./micrometer-core-1.11.5.jar:./ Main

[shakuzen]

Thank you for bringing this to our attention.

I believe this warning is something new since GraalVM 23 perhaps. It did not used to give such a warning. I checked with the latest patch of 22.3 (22.3.3) and it does not give a warning.

It does indeed seem native-image can find the reflect-config.json file now (I assume it did not before) without the native-image.properties. I was trying to find some documentation on this so we can know what minimum version of GraalVM we would be requiring by removing the explicit reference to the reflect-config.json from the native-image.properties. It seems to be documented here, but I'm not sure from what version that became the case. Do you happen to know?

[shakuzen]

I did a little more digging in the documentation, and it looks like GraalVM 22.2 also mentions including the config, but it mentions reflection-config.json rather than reflect-config.json.

[zakkak]

I did a little more digging in the documentation, and it looks like GraalVM 22.2 also mentions including the config, but it mentions reflection-config.json rather than reflect-config.json.

Well it also mentions reflect-config.json in https://www.graalvm.org/22.2/reference-manual/native-image/metadata/#specifying-reflection-metadata-in-json

Digging through the code instead of the documentation I was able to track its presence all the way back to GraalVM 19.1.

Probably GraalVM always detected reflect-config.json but not reflection-config.json (which probably by mistake was mentioned in the docs in the past), thus why there was the need for passing it explicitly through the command line options.

[shakuzen]

Thank you for the investigation and reference. It sounds like we should be okay to remove our native-image.properties in our next minor release, then.