diff --git a/examples/mongo-db-demo/pom.xml b/examples/mongo-db-demo/pom.xml
index 471f134e..f86c68d6 100644
--- a/examples/mongo-db-demo/pom.xml
+++ b/examples/mongo-db-demo/pom.xml
@@ -5,7 +5,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.1.3.RELEASE</version>
+        <version>2.1.8.RELEASE</version>
         <relativePath/> <!-- lookup parent from repository -->
     </parent>
     <groupId>ru.otus.example</groupId>
@@ -15,9 +15,9 @@
     <description>Demo project for MongoDB</description>
 
     <properties>
-        <java.version>1.8</java.version>
-        <maven.compiler.sourcre>1.8.</maven.compiler.sourcre>
-        <maven.compiler.target>1.8</maven.compiler.target>
+        <java.version>11</java.version>
+        <maven.compiler.sourcre>11</maven.compiler.sourcre>
+        <maven.compiler.target>11</maven.compiler.target>
     </properties>
 
     <dependencies>
diff --git a/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/changelogs/InitMongoDBDataChangeLog.java b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/changelogs/InitMongoDBDataChangeLog.java
index b36b0046..c71c7515 100644
--- a/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/changelogs/InitMongoDBDataChangeLog.java
+++ b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/changelogs/InitMongoDBDataChangeLog.java
@@ -30,8 +30,7 @@ public class InitMongoDBDataChangeLog {
 
     @ChangeSet(order = "002", id = "initStudents", author = "stvort", runAlways = true)
     public void initStudents(MongoTemplate template){
-        val student = new Student("Student #1", springDataKnowledge, mongockKnowledge);
-        template.save(student);
+        template.save(new Student("Student #1", springDataKnowledge, mongockKnowledge));
     }
 
     @ChangeSet(order = "003", id = "Teacher", author = "stvort", runAlways = true)
diff --git a/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/repositories/StudentRepositoryCustom.java b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/repositories/StudentRepositoryCustom.java
index 027eec09..8b902bbf 100644
--- a/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/repositories/StudentRepositoryCustom.java
+++ b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/repositories/StudentRepositoryCustom.java
@@ -1,6 +1,12 @@
 package ru.otus.example.mongodbdemo.repositories;
 
+import ru.otus.example.mongodbdemo.model.Knowledge;
+
+import java.util.List;
+
 public interface StudentRepositoryCustom {
+    List<Knowledge> getStudentExperienceById(String studentId);
+
     long getExperienceArrayLengthByStudentId(String id);
     void removeExperienceArrayElementsById(String id);
 }
diff --git a/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/repositories/StudentRepositoryCustomImpl.java b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/repositories/StudentRepositoryCustomImpl.java
index 8d734a09..91fb3536 100644
--- a/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/repositories/StudentRepositoryCustomImpl.java
+++ b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/repositories/StudentRepositoryCustomImpl.java
@@ -3,15 +3,22 @@ package ru.otus.example.mongodbdemo.repositories;
 import lombok.Data;
 import lombok.RequiredArgsConstructor;
 import lombok.val;
+import org.bson.Document;
 import org.bson.types.ObjectId;
 import org.springframework.data.mongodb.core.MongoTemplate;
 import org.springframework.data.mongodb.core.aggregation.Aggregation;
 import org.springframework.data.mongodb.core.query.Criteria;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.core.query.Update;
+import ru.otus.example.mongodbdemo.model.Knowledge;
 import ru.otus.example.mongodbdemo.model.Student;
+import ru.otus.example.mongodbdemo.utils.RawResultPrinter;
 
 
+import java.util.List;
+
+import static org.springframework.data.mongodb.core.aggregation.Aggregation.*;
+import static org.springframework.data.mongodb.core.aggregation.ObjectOperators.ObjectToArray.valueOfToArray;
 import static org.springframework.data.mongodb.core.query.Criteria.where;
 
 @RequiredArgsConstructor
@@ -23,16 +30,36 @@ public class StudentRepositoryCustomImpl implements StudentRepositoryCustom {
     }
 
     private final MongoTemplate mongoTemplate;
+    private final RawResultPrinter rawResultPrinter;
 
-    public long getExperienceArrayLengthByStudentId(String id) {
+    @Override
+    public List<Knowledge> getStudentExperienceById(String studentId) {
+        Aggregation aggregation = newAggregation(
+                match(Criteria.where("id").is(studentId))
+                , unwind("experience")
+                , project().andExclude("_id").and(valueOfToArray("experience")).as("experience_map")
+                , project().and("experience_map").arrayElementAt(1).as("experience_id_map")
+                , project().and("experience_id_map.v").as("experience_id")
+                , lookup("knowledge", "experience_id", "_id", "experience")
+                , project().and("experience._id").as("_id").and("experience.name").as("name")
+        );
+
+        Document rawResults = mongoTemplate.aggregate(aggregation, Student.class, Knowledge.class).getRawResults();
+        rawResultPrinter.prettyPrintRawResult(rawResults);
+        return mongoTemplate.aggregate(aggregation, Student.class, Knowledge.class).getMappedResults();
+    }
+
+    @Override
+    public long getExperienceArrayLengthByStudentId(String studentId) {
         val aggregation = Aggregation.newAggregation(
-                Aggregation.match(where("id").is(id)),
-                Aggregation.project().andExclude("_id").and("experience").size().as("size"));
+                match(where("id").is(studentId)),
+                project().andExclude("_id").and("experience").size().as("size"));
 
         val arraySizeProjection = mongoTemplate.aggregate(aggregation, Student.class, ArraySizeProjection.class).getUniqueMappedResult();
         return arraySizeProjection == null ? 0 : arraySizeProjection.getSize();
     }
 
+    @Override
     public void removeExperienceArrayElementsById(String id) {
         val query = Query.query(Criteria.where("$id").is(new ObjectId(id)));
         val update = new Update().pull("experience", query);
diff --git a/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/utils/RawResultPrinter.java b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/utils/RawResultPrinter.java
new file mode 100644
index 00000000..e033d42d
--- /dev/null
+++ b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/utils/RawResultPrinter.java
@@ -0,0 +1,8 @@
+package ru.otus.example.mongodbdemo.utils;
+
+import org.bson.Document;
+
+public interface RawResultPrinter {
+    @SuppressWarnings("unchecked")
+    void prettyPrintRawResult(Document document);
+}
diff --git a/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/utils/RawResultPrinterImpl.java b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/utils/RawResultPrinterImpl.java
new file mode 100644
index 00000000..1fcd9a7c
--- /dev/null
+++ b/examples/mongo-db-demo/src/main/java/ru/otus/example/mongodbdemo/utils/RawResultPrinterImpl.java
@@ -0,0 +1,18 @@
+package ru.otus.example.mongodbdemo.utils;
+
+import org.bson.Document;
+import org.springframework.stereotype.Component;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+@Component
+public class RawResultPrinterImpl implements RawResultPrinter {
+    @SuppressWarnings("unchecked")
+    @Override
+    public void prettyPrintRawResult(Document document) {
+        List<Document> results = (List<Document>) document.get("results");
+        String resultsAsString = results.stream().map(Document::toString).collect(Collectors.joining("\n"));
+        System.out.println(resultsAsString);
+    }
+}
diff --git a/examples/mongo-db-demo/src/main/resources/application.yml b/examples/mongo-db-demo/src/main/resources/application.yml
index 6f2c5b5a..4d338124 100644
--- a/examples/mongo-db-demo/src/main/resources/application.yml
+++ b/examples/mongo-db-demo/src/main/resources/application.yml
@@ -4,3 +4,6 @@ spring:
       uri: mongodb://localhost
       port: 27017
       database: awesomeMongo
+logging:
+  level:
+    root: ERROR
\ No newline at end of file
diff --git a/examples/mongo-db-demo/src/test/java/ru/otus/example/mongodbdemo/repositories/AbstractRepositoryTest.java b/examples/mongo-db-demo/src/test/java/ru/otus/example/mongodbdemo/repositories/AbstractRepositoryTest.java
index e3723a05..f1342168 100644
--- a/examples/mongo-db-demo/src/test/java/ru/otus/example/mongodbdemo/repositories/AbstractRepositoryTest.java
+++ b/examples/mongo-db-demo/src/test/java/ru/otus/example/mongodbdemo/repositories/AbstractRepositoryTest.java
@@ -3,11 +3,12 @@ package ru.otus.example.mongodbdemo.repositories;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.test.autoconfigure.data.mongo.DataMongoTest;
 import org.springframework.context.annotation.ComponentScan;
-import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.context.annotation.Import;
+import ru.otus.example.mongodbdemo.utils.RawResultPrinterImpl;
 
 @DataMongoTest
 @EnableConfigurationProperties
 @ComponentScan({"ru.otus.example.mongodbdemo.config", "ru.otus.example.mongodbdemo.repositories"})
-@DirtiesContext(classMode = DirtiesContext.ClassMode.AFTER_EACH_TEST_METHOD)
+@Import(RawResultPrinterImpl.class)
 public abstract class AbstractRepositoryTest {
 }
diff --git a/examples/mongo-db-demo/src/test/java/ru/otus/example/mongodbdemo/repositories/withlisteners/StudentRepositoryWithListenersTest.java b/examples/mongo-db-demo/src/test/java/ru/otus/example/mongodbdemo/repositories/withlisteners/StudentRepositoryWithListenersTest.java
index 94533d52..f70740c8 100644
--- a/examples/mongo-db-demo/src/test/java/ru/otus/example/mongodbdemo/repositories/withlisteners/StudentRepositoryWithListenersTest.java
+++ b/examples/mongo-db-demo/src/test/java/ru/otus/example/mongodbdemo/repositories/withlisteners/StudentRepositoryWithListenersTest.java
@@ -10,6 +10,8 @@ import ru.otus.example.mongodbdemo.model.Student;
 import ru.otus.example.mongodbdemo.repositories.AbstractRepositoryTest;
 import ru.otus.example.mongodbdemo.repositories.StudentRepository;
 
+import java.util.List;
+
 import static org.assertj.core.api.Assertions.assertThat;
 
 @DisplayName("StudentRepository при наличии listener-ов в контексте ")
@@ -28,4 +30,12 @@ class StudentRepositoryWithListenersTest extends AbstractRepositoryTest {
         assertThat(actual.getName()).isEqualTo(student.getName());
     }
 
+    @DisplayName("должен возвращать корректный список знаний студента")
+    @Test
+    void shouldReturnCorrectStudentKnowledgeList(){
+        val student = studentRepository.findAll().get(0);
+        List<Knowledge> knowledgeList = studentRepository.getStudentExperienceById(student.getId());
+        assertThat(knowledgeList).containsExactlyInAnyOrderElementsOf(student.getExperience());
+    }
+
 }
diff --git a/examples/mongo-db-demo/src/test/resources/application.yml b/examples/mongo-db-demo/src/test/resources/application.yml
index 8b39c9df..e4a55735 100644
--- a/examples/mongo-db-demo/src/test/resources/application.yml
+++ b/examples/mongo-db-demo/src/test/resources/application.yml
@@ -5,4 +5,7 @@ spring:
       database: test
       #uri: mongodb://localhost
       #port: 27017
-      #database: awesomeMongo
\ No newline at end of file
+      #database: awesomeMongo
+logging:
+  level:
+    root: ERROR
\ No newline at end of file