BAEL-3828 Where Should @Service Annotation Be Kept? (#10430)

* BAEL-3828 add code samples and tests for the article

* BAEL-3828 fix maven test folder structure and test executions

* BAEL-3828 fix indentation in continuation lines

spring-boot-modules/spring-boot-annotations/src/main/java/com/baeldung/annotations/service/AuthApplication.java

@@ -0,0 +1,22 @@
+package com.baeldung.annotations.service;
+
+import com.baeldung.annotations.service.abstracts.AbstractAuthenticationService;
+import com.baeldung.annotations.service.interfaces.AuthenticationService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class AuthApplication {
+
+    @Autowired
+    private AuthenticationService inMemoryAuthService;
+
+    @Autowired
+    private AbstractAuthenticationService ldapAuthService;
+
+    public static void main(String[] args) {
+        SpringApplication.run(AuthApplication.class, args);
+    }
+
+}

spring-boot-modules/spring-boot-annotations/src/main/java/com/baeldung/annotations/service/abstracts/AbstractAuthenticationService.java

@@ -0,0 +1,12 @@
+package com.baeldung.annotations.service.abstracts;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public abstract class AbstractAuthenticationService {
+
+    public boolean authenticate(String username, String password) {
+        return false;
+    }
+
+}

spring-boot-modules/spring-boot-annotations/src/main/java/com/baeldung/annotations/service/concretes/InMemoryAuthenticationService.java

@@ -0,0 +1,14 @@
+package com.baeldung.annotations.service.concretes;
+
+import com.baeldung.annotations.service.interfaces.AuthenticationService;
+import org.springframework.stereotype.Service;
+
+@Service
+public class InMemoryAuthenticationService implements AuthenticationService {
+
+    @Override
+    public boolean authenticate(String username, String password) {
+        return false;
+    }
+
+}

spring-boot-modules/spring-boot-annotations/src/main/java/com/baeldung/annotations/service/concretes/LdapAuthenticationService.java

@@ -0,0 +1,14 @@
+package com.baeldung.annotations.service.concretes;
+
+import com.baeldung.annotations.service.abstracts.AbstractAuthenticationService;
+import org.springframework.stereotype.Service;
+
+@Service
+public class LdapAuthenticationService extends AbstractAuthenticationService {
+
+    @Override
+    public boolean authenticate(String username, String password) {
+        return true;
+    }
+
+}

spring-boot-modules/spring-boot-annotations/src/main/java/com/baeldung/annotations/service/interfaces/AuthenticationService.java

@@ -0,0 +1,10 @@
+package com.baeldung.annotations.service.interfaces;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public interface AuthenticationService {
+
+    boolean authenticate(String username, String password);
+
+}

spring-boot-modules/spring-boot-annotations/src/test/java/com.baeldung.annotations/EmployeeApplicationUnitTest.java

@@ -6,7 +6,7 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.junit.jupiter.api.Assertions.assertAll;
 
-public class EmployeeApplicationTest {
+public class EmployeeApplicationUnitTest {
     private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
             .withUserConfiguration(EmployeeApplication.class);
 

spring-boot-modules/spring-boot-annotations/src/test/java/com.baeldung.annotations/service/AuthApplicationUnitTest.java

@@ -0,0 +1,51 @@
+package com.baeldung.annotations.service;
+
+import com.baeldung.annotations.service.abstracts.AbstractAuthenticationService;
+import com.baeldung.annotations.service.config.AbstractsAnnotatedTestConfiguration;
+import com.baeldung.annotations.service.config.ConcreteClassesAnnotatedTestConfiguration;
+import com.baeldung.annotations.service.config.InterfacesAnnotatedTestConfiguration;
+import com.baeldung.annotations.service.interfaces.AuthenticationService;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+
+public class AuthApplicationUnitTest {
+
+    private final ApplicationContextRunner contextRunner = new ApplicationContextRunner();
+
+    @Test
+    void whenOnlyInterfacesAnnotated_noSuchBeanDefinitionExceptionThrown() {
+        contextRunner
+          .withUserConfiguration(InterfacesAnnotatedTestConfiguration.class)
+          .run(context -> {
+              Assertions.assertThrows(NoSuchBeanDefinitionException.class, () -> {
+                  context.getBean(AuthenticationService.class);
+              });
+          });
+    }
+
+    @Test
+    void whenOnlyAbstractClassesAnnotated_noSuchBeanDefinitionExceptionThrown() {
+        contextRunner
+          .withUserConfiguration(AbstractsAnnotatedTestConfiguration.class)
+          .run(context -> {
+              Assertions.assertThrows(NoSuchBeanDefinitionException.class, () -> {
+                  context.getBean(AbstractAuthenticationService.class);
+              });
+          });
+    }
+
+    @Test
+    void whenConcreteClassesAnnotated_noExceptionThrown() {
+        contextRunner
+          .withUserConfiguration(ConcreteClassesAnnotatedTestConfiguration.class)
+          .run(context -> {
+              AuthenticationService inMemoryAuthService = context.getBean(AuthenticationService.class);
+              AbstractAuthenticationService ldapAuthService = context.getBean(AbstractAuthenticationService.class);
+
+              Assertions.assertNotNull(inMemoryAuthService);
+              Assertions.assertNotNull(ldapAuthService);
+          });
+    }
+}

spring-boot-modules/spring-boot-annotations/src/test/java/com.baeldung.annotations/service/config/AbstractsAnnotatedTestConfiguration.java

@@ -0,0 +1,10 @@
+package com.baeldung.annotations.service.config;
+
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.ComponentScan;
+
+@TestConfiguration
+@ComponentScan("com.baeldung.annotations.service.abstracts")
+public class AbstractsAnnotatedTestConfiguration {
+
+}

spring-boot-modules/spring-boot-annotations/src/test/java/com.baeldung.annotations/service/config/ConcreteClassesAnnotatedTestConfiguration.java

@@ -0,0 +1,10 @@
+package com.baeldung.annotations.service.config;
+
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.ComponentScan;
+
+@TestConfiguration
+@ComponentScan("com.baeldung.annotations.service.concretes")
+public class ConcreteClassesAnnotatedTestConfiguration {
+
+}

spring-boot-modules/spring-boot-annotations/src/test/java/com.baeldung.annotations/service/config/InterfacesAnnotatedTestConfiguration.java

@@ -0,0 +1,10 @@
+package com.baeldung.annotations.service.config;
+
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.ComponentScan;
+
+@TestConfiguration
+@ComponentScan("com.baeldung.annotations.service.interfaces")
+public class InterfacesAnnotatedTestConfiguration {
+
+}