Add graalvm-native-images: Boot 4.1 + GraalVM CE for JDK 25, AOT processing,

the tracing agent, and a real reflection-collision trap

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EQNA6DJ9VgCtW6zhCE8Xud

graalvm-native-images/src/main/java/com/ankurm/graalvmdemo/GraalvmDemoApplication.java

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+package com.ankurm.graalvmdemo;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Companion app for the ankurm.com GraalVM native images post. Built three ways from the same
+ * source: a plain {@code java -jar}, a Spring Boot AOT-processed JVM run, and a GraalVM native
+ * image. See docs/02-building-the-image.md for the exact commands behind each measurement.
+ */
+@SpringBootApplication
+public class GraalvmDemoApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(GraalvmDemoApplication.class, args);
+    }
+}

graalvm-native-images/src/main/java/com/ankurm/graalvmdemo/HelloController.java

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+package com.ankurm.graalvmdemo;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * The baseline endpoint used for every startup-time and memory measurement in this chapter --
+ * deliberately trivial, so the numbers reflect the framework and the runtime, not application
+ * work. See docs/01-building-the-image.md.
+ */
+@RestController
+public class HelloController {
+
+    @GetMapping("/hello")
+    public String hello() {
+        return "Hello from a GraalVM native image!";
+    }
+}

graalvm-native-images/src/main/java/com/ankurm/graalvmdemo/report/JsonReport.java

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+package com.ankurm.graalvmdemo.report;
+
+public class JsonReport implements ReportFormat {
+    @Override
+    public String render(String message) {
+        return "{\"report\":\"" + message + "\"}";
+    }
+}

graalvm-native-images/src/main/java/com/ankurm/graalvmdemo/report/PlainTextReport.java

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+package com.ankurm.graalvmdemo.report;
+
+public class PlainTextReport implements ReportFormat {
+    @Override
+    public String render(String message) {
+        return "REPORT: " + message;
+    }
+}

graalvm-native-images/src/main/java/com/ankurm/graalvmdemo/report/ReportController.java

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+package com.ankurm.graalvmdemo.report;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * Loads a {@link ReportFormat} implementation by a class name built at request time from the
+ * {@code format} query parameter -- a stand-in for the real-world "pluggable strategy resolved by
+ * a string from configuration" pattern (a plugin name, a feature flag, a database column).
+ * Nothing here gives GraalVM's build-time static analysis a way to know which classes this
+ * reflective call can reach; see docs/02-the-reflection-trap.md for the real failure and its fix.
+ */
+@RestController
+public class ReportController {
+
+    @GetMapping("/report")
+    public String report(@RequestParam(defaultValue = "plain") String format, @RequestParam(defaultValue = "quarterly numbers") String message) {
+        String simpleName = "plain".equals(format) ? "PlainTextReport" : "JsonReport";
+        String className = "com.ankurm.graalvmdemo.report." + simpleName;
+        try {
+            Class<?> clazz = Class.forName(className);
+            ReportFormat instance = (ReportFormat) clazz.getDeclaredConstructor().newInstance();
+            return "OK via reflection on " + className + ": " + instance.render(message);
+        } catch (ReflectiveOperationException e) {
+            return "REFLECTION-FAILED class=" + className + " exception=" + e.getClass().getName() + " message=" + e.getMessage();
+        }
+    }
+}

graalvm-native-images/src/main/java/com/ankurm/graalvmdemo/report/ReportFormat.java

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+package com.ankurm.graalvmdemo.report;
+
+/**
+ * Deliberately loaded by class name at runtime, never referenced by a Spring bean definition or a
+ * static {@code new PlainTextReport()} anywhere in this codebase -- see docs/02-the-reflection-trap.md
+ * for why that specific shape is what breaks under GraalVM's closed-world analysis.
+ */
+public interface ReportFormat {
+    String render(String message);
+}

graalvm-native-images/src/main/resources/META-INF/native-image/com.ankurm.graalvmdemo/manual-hints/reachability-metadata.json

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+{
+  "reflection": [
+    {
+      "type": "com.ankurm.graalvmdemo.report.PlainTextReport",
+      "methods": [
+        { "name": "<init>", "parameterTypes": [] }
+      ]
+    },
+    {
+      "type": "com.ankurm.graalvmdemo.report.JsonReport",
+      "methods": [
+        { "name": "<init>", "parameterTypes": [] }
+      ]
+    }
+  ]
+}

graalvm-native-images/src/main/resources/application.yml

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+spring:
+  application:
+    name: graalvm-native-images
+
+management:
+  endpoints:
+    web:
+      exposure:
+        include: health
+
+logging:
+  pattern:
+    console: "%msg%n"