Fix problem for Spring

src/main/java/dev/struchkov/example/spring/nbfe/ListenerForRun.java

@@ -0,0 +1,24 @@
+package dev.struchkov.example.spring.nbfe;
+
+import dev.struchkov.example.spring.nbfe.domain.Post;
+import dev.struchkov.example.spring.nbfe.service.PostService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.boot.ApplicationArguments;
+import org.springframework.boot.ApplicationRunner;
+import org.springframework.stereotype.Component;
+
+import java.util.List;
+
+@Component
+@RequiredArgsConstructor
+public class ListenerForRun implements ApplicationRunner {
+
+    private final PostService postService;
+
+    @Override
+    public void run(ApplicationArguments args) throws Exception {
+        final List<Post> allWithCommentsAndTags = postService.findAllWithCommentsAndTags(1, 50);
+        System.out.println();
+    }
+
+}

src/main/java/dev/struchkov/example/spring/nbfe/SpringApp.java

@@ -1,31 +1,15 @@
 package dev.struchkov.example.spring.nbfe;
 
-import dev.struchkov.example.spring.nbfe.domain.Post;
-import dev.struchkov.example.spring.nbfe.repository.PostRepository;
-import lombok.RequiredArgsConstructor;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.context.event.ContextStartedEvent;
-import org.springframework.context.event.EventListener;
-
-import java.util.List;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
 
 @SpringBootApplication
-@RequiredArgsConstructor
+@EnableTransactionManagement
 public class SpringApp {
 
-    private final PostRepository postRepository;
-
     public static void main(String[] args) {
         SpringApplication.run(SpringApp.class, args);
     }
 
-    @EventListener
-    public void run(ContextStartedEvent event) {
-        final long start = System.currentTimeMillis();
-        final List<Post> allWithCommentsAndTags = postRepository.findAllWithCommentsAndTags(1, 50);
-        final long finish = System.currentTimeMillis();
-        System.out.println(finish - start);
-    }
-
 }

src/main/java/dev/struchkov/example/spring/nbfe/domain/Post.java

@@ -11,12 +11,14 @@ import javax.persistence.JoinColumn;
 import javax.persistence.JoinTable;
 import javax.persistence.ManyToMany;
 import javax.persistence.OneToMany;
+import javax.persistence.Table;
 import java.util.ArrayList;
 import java.util.List;
 
 @Entity
 @Getter
 @Setter
+@Table(name = "POST")
 public class Post {
 
     @Id

src/main/java/dev/struchkov/example/spring/nbfe/domain/PostComment.java

@@ -7,10 +7,12 @@ import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.ManyToOne;
+import javax.persistence.Table;
 
 @Entity
 @Getter
 @Setter
+@Table(name = "POSTCOMMENT")
 public class PostComment {
 
     @Id

src/main/java/dev/struchkov/example/spring/nbfe/domain/Tag.java

@@ -11,6 +11,7 @@ import javax.persistence.Table;
 @Entity
 @Getter
 @Setter
+@Table(name = "TAG")
 public class Tag {
 
     @Id

src/main/java/dev/struchkov/example/spring/nbfe/repository/PostRepository.java

@@ -10,13 +10,23 @@ import java.util.List;
 public interface PostRepository extends JpaRepository<Post, Long> {
 
     @Query("""
-            select distinct p
-            from Post p
-            left join fetch p.comments
-            left join fetch p.tags
-            where p.id between :minId and :maxId
-            """)
-    List<Post> findAllWithCommentsAndTags(
+        select distinct p
+        from Post p
+        left join fetch p.comments
+        where p.id between :minId and :maxId
+        """)
+    List<Post> findAllWithComments(
+            @Param("minId") long minId,
+            @Param("maxId") long maxId
+    );
+
+    @Query("""
+        select distinct p
+        from Post p
+        left join fetch p.tags
+        where p.id between :minId and :maxId
+        """)
+    List<Post> findAllWithTags(
             @Param("minId") long minId,
             @Param("maxId") long maxId
     );

src/main/java/dev/struchkov/example/spring/nbfe/service/PostService.java

@@ -0,0 +1,33 @@
+package dev.struchkov.example.spring.nbfe.service;
+
+import dev.struchkov.example.spring.nbfe.domain.Post;
+import dev.struchkov.example.spring.nbfe.repository.PostRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.List;
+
+@Service
+@RequiredArgsConstructor
+public class PostService {
+
+    private final PostRepository postRepository;
+
+    @Transactional(readOnly = true)
+    public List<Post> findAllWithCommentsAndTags(long minId, long maxId) {
+
+        final List<Post> posts = postRepository.findAllWithComments(
+                minId,
+                maxId
+        );
+
+        return !posts.isEmpty() ?
+                postRepository.findAllWithTags(
+                        minId,
+                        maxId
+                ) :
+                posts;
+    }
+
+}

src/main/resources/application.yml

@@ -1,6 +1,14 @@
 spring:
+  datasource:
+    driver-class-name: org.h2.Driver
+    url: jdbc:h2:file:./data/demo
+    username: sa
+    password:
   jpa:
     show-sql: true
+    database-platform: org.hibernate.dialect.H2Dialect
     properties:
       hibernate:
         format_sql: true
+    hibernate:
+      ddl-auto: none

src/main/resources/logback.xml

@@ -5,8 +5,7 @@
         </encoder>
     </appender>
 
-    <logger name="org.hibernate.SQL" level="DEBUG" />
-    <logger name="org.hibernate.type" level="TRACE" />
+    <logger name="org.hibernate.engine.transaction.internal.TransactionImpl" level="DEBUG"/>
 
     <root level="info">
         <appender-ref ref="STDOUT"/>