Adjust GraalVM Native substitutions for JMXFetch

Author: ygree

dd-java-agent/instrumentation/graal/native-image/src/main/java/datadog/trace/instrumentation/graal/nativeimage/Target_org_datadog_jmxfetch_App.java

@@ -7,15 +7,11 @@
 public final class Target_org_datadog_jmxfetch_App {
   @Substitute
   private boolean getJsonConfigs() {
-    // Replace org.datadog.jmxfetch.App.getJsonConfigs to fix the GraalVM native build error.
-    //
-    // This method has references to the excluded transitive dependencies:
-    // - jackson-core (catch JsonProcessingException)
-    // - jackson-jr-objects (referenced in org.datadog.jmxfetch.JsonParser).
+    // This method has a reference to the excluded transitive dependency jackson-jr-objects.
     // GraalVM Native detects it during the reachability analysis and results in
     // "Discovered unresolved method during parsing:
     // org.datadog.jmxfetch.App.<init>(org.datadog.jmxfetch.AppConfig)."
     // because of the missing classes that belong to the excluded dependencies.
-    return false;
+    throw new IllegalStateException("Unreachable");
   }
 }

dd-java-agent/instrumentation/graal/native-image/src/main/java/datadog/trace/instrumentation/graal/nativeimage/Target_org_datadog_jmxfetch_Status.java

@@ -8,12 +8,10 @@
 public final class Target_org_datadog_jmxfetch_Status {
   @Substitute
   private String generateJson() throws IOException {
-    // Replace org.datadog.jmxfetch.Status.generateJson to fix the GraalVM native build error.
-    //
     // This method has a reference to the excluded transitive dependency jackson-jr-objects.
     // GraalVM Native detects it during the reachability analysis and results in
     // "Discovered unresolved type during parsing: com.fasterxml.jackson.jr.ob.JSON."
     // because of the missing classes that belong to the excluded dependencies.
-    return "";
+    throw new IllegalStateException("Unreachable");
   }
 }

dd-java-agent/instrumentation/graal/native-image/src/main/java/datadog/trace/instrumentation/graal/nativeimage/Target_org_datadog_jmxfetch_reporter_JsonReporter.java

@@ -8,12 +8,10 @@ public final class Target_org_datadog_jmxfetch_reporter_JsonReporter {
   @Substitute
   public void doSendServiceCheck(
       String serviceCheckName, String status, String message, String[] tags) {
-    // Replace org.datadog.jmxfetch.reporter.JsonReporter.doSendServiceCheck to fix the GraalVM
-    // native build error.
-    //
     // This method has a reference to the excluded transitive dependency jackson-jr-objects.
     // GraalVM Native detects it during the reachability analysis and results in
     // "Discovered unresolved type during parsing: com.fasterxml.jackson.jr.ob.JSON."
     // because of the missing classes that belong to the excluded dependencies.
+    throw new IllegalStateException("Unreachable");
   }
 }