eugenp · davidmartinezbarua · May 12, 2025 · Apr 28, 2025 · May 11, 2025
diff --git a/spring-aop-2/src/main/java/com/baeldung/internalaop/AddComponent.java b/spring-aop-2/src/main/java/com/baeldung/internalaop/AddComponent.java
@@ -0,0 +1,32 @@
+package com.baeldung.internalaop;
+
+import org.springframework.cache.annotation.CacheConfig;
+import org.springframework.cache.annotation.CacheEvict;
+import org.springframework.cache.annotation.Cacheable;
+import org.springframework.stereotype.Component;
+
+@Component
+@CacheConfig(cacheNames = "addOne")
+public class AddComponent {
+
+    private int counter = 0;
+
+    @Cacheable
+    public int addOne(int n) {
+        counter++;
+        return n + 1;
+    }
+
+    public int addOneAndDouble(int n) {
+        return addOne(n) + addOne(n);
+    }
+
+    public int getCounter() {
+        return counter;
+    }
+
+    @CacheEvict(allEntries = true)
+    public void resetCache() {
+        counter = 0;
+    }
+}
diff --git a/spring-aop-2/src/main/java/com/baeldung/internalaop/AddOneAndDoubleComponent.java b/spring-aop-2/src/main/java/com/baeldung/internalaop/AddOneAndDoubleComponent.java
@@ -0,0 +1,16 @@
+package com.baeldung.internalaop;
+
+import jakarta.annotation.Resource;
+
+import org.springframework.stereotype.Component;
+
+@Component
+public class AddOneAndDoubleComponent {
+
+    @Resource
+    private AddComponent addComponent;
+
+    public int addOneAndDouble(int n) {
+        return addComponent.addOne(n) + addComponent.addOne(n);
+    }
+}
diff --git a/spring-aop-2/src/main/java/com/baeldung/internalaop/SelfInjection.java b/spring-aop-2/src/main/java/com/baeldung/internalaop/SelfInjection.java
@@ -0,0 +1,39 @@
+package com.baeldung.internalaop;
+
+import jakarta.annotation.Resource;
+
+import org.springframework.cache.annotation.CacheConfig;
+import org.springframework.cache.annotation.CacheEvict;
+import org.springframework.cache.annotation.Cacheable;
+import org.springframework.context.annotation.Lazy;
+import org.springframework.stereotype.Component;
+
+@Component
+@CacheConfig(cacheNames = "selfInjectionAddOne")
+public class SelfInjection {
+
+    @Lazy
+    @Resource
+    private SelfInjection selfInjection;
+
+    private int counter = 0;
+
+    @Cacheable
+    public int addOne(int n) {
+        counter++;
+        return n + 1;
+    }
+
+    public int addOneAndDouble(int n) {
+        return selfInjection.addOne(n) + selfInjection.addOne(n);
+    }
+
+    public int getCounter() {
+        return counter;
+    }
+
+    @CacheEvict(allEntries = true)
+    public void resetCache() {
+        counter = 0;
+    }
+}
diff --git a/spring-aop-2/src/test/java/com/baeldung/internalaop/AddComponentUnitTest.java b/spring-aop-2/src/test/java/com/baeldung/internalaop/AddComponentUnitTest.java
@@ -0,0 +1,37 @@
+package com.baeldung.internalaop;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import jakarta.annotation.Resource;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import com.baeldung.Application;
+
+@SpringBootTest(classes = Application.class)
+class AddComponentUnitTest {
+
+    @Resource
+    private AddComponent addComponent;
+
+    @Test
+    void whenInternalCall_thenCacheNotHit() {
+        addComponent.resetCache();
+
+        addComponent.addOneAndDouble(0);
+
+        assertThat(addComponent.getCounter()).isEqualTo(2);
+    }
+
+    @Test
+    void whenExternalCall_thenCacheHit() {
+        addComponent.resetCache();
+
+        addComponent.addOne(0);
+        addComponent.addOne(0);
+
+        assertThat(addComponent.getCounter()).isEqualTo(1);
+    }
+
+}
diff --git a/spring-aop-2/src/test/java/com/baeldung/internalaop/AddOneAndDoubleComponentUnitTest.java b/spring-aop-2/src/test/java/com/baeldung/internalaop/AddOneAndDoubleComponentUnitTest.java
@@ -0,0 +1,29 @@
+package com.baeldung.internalaop;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import jakarta.annotation.Resource;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import com.baeldung.Application;
+
+@SpringBootTest(classes = Application.class)
+class AddOneAndDoubleComponentUnitTest {
+
+    @Resource
+    private AddOneAndDoubleComponent addOneAndDoubleComponent;
+
+    @Resource
+    private AddComponent addComponent;
+
+    @Test
+    void whenCallingFromExternalClass_thenAopProxyIsUsed() {
+        addComponent.resetCache();
+
+        addOneAndDoubleComponent.addOneAndDouble(0);
+
+        assertThat(addComponent.getCounter()).isEqualTo(1);
+    }
+}
diff --git a/spring-aop-2/src/test/java/com/baeldung/internalaop/SelfInjectionUnitTest.java b/spring-aop-2/src/test/java/com/baeldung/internalaop/SelfInjectionUnitTest.java
@@ -0,0 +1,26 @@
+package com.baeldung.internalaop;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import jakarta.annotation.Resource;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import com.baeldung.Application;
+
+@SpringBootTest(classes = Application.class)
+class SelfInjectionUnitTest {
+
+    @Resource
+    private SelfInjection selfInjection;
+
+    @Test
+    void whenCallingFromExternalClass_thenAopProxyIsUsed() {
+        selfInjection.resetCache();
+
+        selfInjection.addOneAndDouble(0);
+
+        assertThat(selfInjection.getCounter()).isEqualTo(1);
+    }
+}