Document how to handle MANIFEST.MF in native image with Maven #42412
Description
When native image is built, there is no MANIFEST.MF for the application being built. Running "MyApp.class.getPackage().getImplementationVersion()" will return "null" in such scenario.
This is expected, as MANIFEST.MF is written by maven-jar-plugin, but native image build operates on target/classes dir itself.
How would one proceed with "get version of the currently running app" when running as native executable?
Consider the following example: https://github.com/krezovic/native-image-demo
@SpringBootApplication public class DemoApplication { private static final String VERSION; static { VERSION = DemoApplication.class.getPackage().getImplementationVersion(); } public static void main(String[] args) { log.info("Running version: {}", VERSION); SpringApplication.run(DemoApplication.class, args); } } ./mvnw clean package -P native ./mvnw native:compile will produce
$ ls -l target total 104128 drwxr-xr-x 5 armin armin 4096 Sep 22 13:45 classes -rwxr-xr-x 1 armin armin 85846072 Sep 22 13:46 demo -rw-r--r-- 1 armin armin 20596296 Sep 22 13:45 demo-0.0.1-SNAPSHOT.jar -rw-r--r-- 1 armin armin 137454 Sep 22 13:45 demo-0.0.1-SNAPSHOT.jar.original drwxr-xr-x 3 armin armin 4096 Sep 22 13:45 generated-sources drwxr-xr-x 3 armin armin 4096 Sep 22 13:45 generated-test-sources drwxr-xr-x 3 armin armin 4096 Sep 22 13:45 graalvm-reachability-metadata drwxr-xr-x 2 armin armin 4096 Sep 22 13:45 maven-archiver drwxr-xr-x 3 armin armin 4096 Sep 22 13:45 maven-status drwxr-xr-x 3 armin armin 4096 Sep 22 13:45 spring-aot drwxr-xr-x 2 armin armin 4096 Sep 22 13:45 surefire-reports drwxr-xr-x 3 armin armin 4096 Sep 22 13:45 test-classes drwxr-xr-x 2 armin armin 4096 Sep 22 13:45 test-ids Running
$ java -jar target/demo-0.0.1-SNAPSHOT.jar 13:47:41.896 [main] INFO com.example.demo.DemoApplication -- Running version: 0.0.1-SNAPSHOT Running native executable, however
$ target/demo 13:48:04.685 [main] INFO com.example.demo.DemoApplication -- Running version: null As expected, there's no MANIFEST.MF inside target/classes/META-INF
$ ls -l target/classes/META-INF total 4 drwxr-xr-x 6 armin armin 4096 Sep 22 13:45 native-image It is only present inside final JAR file
$ jar -tf target/demo-0.0.1-SNAPSHOT.jar | grep META-INF META-INF/ META-INF/MANIFEST.MF META-INF/services/ META-INF/services/java.nio.file.spi.FileSystemProvider META-INF/native-image/ META-INF/native-image/ch.qos.logback/ META-INF/native-image/ch.qos.logback/logback-classic/ META-INF/native-image/ch.qos.logback/logback-classic/1.5.8/ META-INF/native-image/com.example/ META-INF/native-image/com.example/demo/ META-INF/native-image/com.fasterxml.jackson.core/ META-INF/native-image/com.fasterxml.jackson.core/jackson-databind/ META-INF/native-image/com.fasterxml.jackson.core/jackson-databind/2.17.2/ META-INF/native-image/org.apache.tomcat.embed/ META-INF/native-image/org.apache.tomcat.embed/tomcat-embed-core/ META-INF/native-image/org.apache.tomcat.embed/tomcat-embed-core/10.1.30/ META-INF/maven/ META-INF/maven/com.example/ META-INF/maven/com.example/demo/ META-INF/native-image/ch.qos.logback/logback-classic/1.5.8/reflect-config.json META-INF/native-image/ch.qos.logback/logback-classic/1.5.8/resource-config.json META-INF/native-image/com.example/demo/reflect-config.json META-INF/native-image/com.example/demo/resource-config.json META-INF/native-image/com.example/demo/native-image.properties META-INF/native-image/com.fasterxml.jackson.core/jackson-databind/2.17.2/reflect-config.json META-INF/native-image/org.apache.tomcat.embed/tomcat-embed-core/10.1.30/reflect-config.json META-INF/native-image/org.apache.tomcat.embed/tomcat-embed-core/10.1.30/resource-config.json META-INF/maven/com.example/demo/pom.xml META-INF/maven/com.example/demo/pom.properties