Make sample application work in native image with dynamic proxies

Author: sbrannen

src/main/java/org/example/demo/Config.java

@@ -1,14 +1,13 @@
 package org.example.demo;
 
-import org.example.demo.service.Service;
 import org.example.demo.service.ServiceImpl;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
-@Configuration
+@Configuration(proxyBeanMethods = false)
 public class Config {
   @Bean
-  public Service service() {
+  public ServiceImpl service() {
     return new ServiceImpl(42);
   }
 }

src/main/java/org/example/demo/Controller.java

@@ -15,7 +15,7 @@ public Controller(Service service) {
   }
 
   @GetMapping("/hello")
-  String hello() {
-    return "World" + service.getConstant();
+  public String hello() {
+    return "Hello, World " + service.getConstant();
   }
 }

src/main/java/org/example/demo/DemoApplication.java

@@ -3,7 +3,7 @@
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 
-@SpringBootApplication
+@SpringBootApplication(proxyBeanMethods = false)
 public class DemoApplication {
 
 	public static void main(String[] args) {

src/main/java/org/example/demo/aspect/LoggingAspect.java

@@ -1,6 +1,9 @@
 package org.example.demo.aspect;
 
 import jakarta.validation.constraints.NotNull;
+import java.util.ArrayList;
+import java.util.List;
+
 import org.aspectj.lang.ProceedingJoinPoint;
 import org.aspectj.lang.annotation.Around;
 import org.aspectj.lang.annotation.Aspect;
@@ -10,11 +13,20 @@
 @Component
 public class LoggingAspect {
 
+  public final List<String> intercepted = new ArrayList<>();
+
   @Around(
-      "within(org.example.demo..*) && execution(public * *(..)) && @target(org.example.demo.aspect.AutomaticLogger)")
+      "within(org.example.demo..*) && execution(public * *(..)) && @within(org.example.demo.aspect.AutomaticLogger)")
   public Object log(@NotNull ProceedingJoinPoint jp) throws Throwable {
+    intercepted.add(jp.getSignature().getDeclaringType().getCanonicalName() + "." + jp.getSignature().getName());
+
     Object result = jp.proceed(jp.getArgs());
 
+    if (result instanceof Integer number) {
+      // modify the value so it can be verified in a test
+      result = number * 2;
+    }
+
     // body removed for simplicity
     return result;
   }

src/main/java/org/example/demo/service/ServiceImpl.java

@@ -1,6 +1,8 @@
 package org.example.demo.service;
 
+import org.example.demo.aspect.AutomaticLogger;
 
+@AutomaticLogger
 public class ServiceImpl implements Service {
   private final Integer constant;
 

src/main/resources/application.properties

@@ -1 +1,2 @@
-spring.application.name=demo
+spring.application.name=demo
+spring.aop.proxy-target-class=false

src/test/java/org/example/demo/SmokeTests.java

@@ -0,0 +1,47 @@
+package org.example.demo;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import org.example.demo.aspect.LoggingAspect;
+import org.example.demo.service.Service;
+import org.junit.jupiter.api.Test;
+import org.springframework.aop.support.AopUtils;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.web.servlet.MockMvc;
+
+@SpringBootTest
+@AutoConfigureMockMvc
+class SmokeTests {
+
+	@Autowired
+	LoggingAspect loggingAspect;
+
+	@Autowired
+	Controller controller;
+
+	@Autowired
+	Service service;
+
+	@Test
+	void accessRestEndpoint(@Autowired MockMvc mockMvc) throws Exception {
+		mockMvc.perform(get("/hello"))
+			.andExpect(status().isOk())
+			.andExpect(content().string("Hello, World 84")); // 84 = 2 * 42
+
+		assertThat(AopUtils.isAopProxy(this.loggingAspect)).isFalse();
+		assertThat(AopUtils.isCglibProxy(this.controller)).isTrue();
+		assertThat(AopUtils.isJdkDynamicProxy(this.service)).isTrue();
+
+		assertThat(this.loggingAspect.intercepted)
+			.containsExactly(
+				"org.example.demo.Controller.hello",
+				"org.example.demo.service.Service.getConstant"
+			);
+	}
+
+}