Merge branch 'eugenp:master' into master

2022-03-05 22:23:01 -03:00
parent 6a9b7f935f 28519a494c
commit 5b399786f6
62 changed files with 1273 additions and 135 deletions
@@ -0,0 +1,67 @@
+package com.baeldung.poi.excel.lastrow;
+
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class LastRowUnitTest {
+    private static final String FILE_NAME = "lastRowTest.xlsx";
+    private String fileLocation;
+
+    @Before
+    public void setup() throws URISyntaxException {
+        fileLocation = Paths.get(ClassLoader.getSystemResource(FILE_NAME).toURI()).toString();
+    }
+
+    @Test
+    public void givenExampleGrid_whenGetRow_thenReturnRowObjectIfModified() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(0);
+
+        assertEquals(7, sheet.getLastRowNum());
+        assertEquals(6, sheet.getPhysicalNumberOfRows());
+
+        assertNotNull(sheet.getRow(0));
+        assertNotNull(sheet.getRow(1));
+        assertNotNull(sheet.getRow(2));
+        assertNotNull(sheet.getRow(3));
+        assertNull(sheet.getRow(4));
+        assertNull(sheet.getRow(5));
+        assertNotNull(sheet.getRow(6));
+        assertNotNull(sheet.getRow(7));
+        assertNull(sheet.getRow(8));
+
+        assertSame(sheet.getRow(7), getLastRowFromSheet(sheet));
+    }
+
+    @Test
+    public void givenEmptySheet_whenGetRow_thenReturnNull() throws IOException {
+        Workbook workbook = new XSSFWorkbook(fileLocation);
+        Sheet sheet = workbook.getSheetAt(1);
+
+        assertEquals(-1, sheet.getLastRowNum());
+        assertEquals(0, sheet.getPhysicalNumberOfRows());
+
+        assertNull(sheet.getRow(0));
+
+        assertSame(sheet.getRow(0), getLastRowFromSheet(sheet));
+    }
+
+    public static Row getLastRowFromSheet(Sheet sheet) {
+        Row lastRow = null;
+        int lastRowNum = sheet.getLastRowNum();
+        if (lastRowNum >= 0) {
+            lastRow = sheet.getRow(lastRowNum);
+        }
+        return lastRow;
+    }
+}
@@ -6,3 +6,5 @@ This module contains articles about Map data structures in Java.
 - [Using a Custom Class as a Key in a Java HashMap](https://www.baeldung.com/java-custom-class-map-key)
 - [Nested HashMaps Examples in Java](https://www.baeldung.com/java-nested-hashmaps)
 - [Java HashMap With Different Value Types](https://www.baeldung.com/java-hashmap-different-value-types)
+- [Difference Between Map and HashMap in Java](https://www.baeldung.com/java-map-vs-hashmap)
+- [How to Create a New Entry in a Map](https://www.baeldung.com/java-map-new-entry)
@@ -4,3 +4,4 @@
 - [Bad Practices With Synchronization](https://www.baeldung.com/java-synchronization-bad-practices)
 - [Start Two Threads at the Exact Same Time in Java](https://www.baeldung.com/java-start-two-threads-at-same-time)
 - [Volatile Variables and Thread Safety](https://www.baeldung.com/java-volatile-variables-thread-safety)
+- [Producer-Consumer Problem With Example in Java](https://www.baeldung.com/java-producer-consumer-problem)
@@ -1,3 +1,4 @@
 ### Relevant Articles:

 - [Java ArrayIndexOutOfBoundsException](https://www.baeldung.com/java-arrayindexoutofboundsexception)
+- [Java Missing Return Statement](https://www.baeldung.com/java-missing-return-statement)
@@ -1,45 +0,0 @@
-package com.baeldung.exception.variablemightnothavebeeninitialized;
-
-public class VariableMightNotHaveBeenInitialized {
-
-    private static int instanceVariableCount;
-
-    /**
-     * Method would not compile if lines 14 and 18 are uncommented.
-     */
-    public static void countEven() {
-        //uninstantiated
-        int count;
-        int[] arr = new int[]{23, 56, 89, 12, 23};
-        for (int i = 0; i < arr.length; i++) {
-            if ((arr[i] % 2) == 0) {
-                // count++;
-            }
-
-        }
-        // System.out.println("Total Even Numbers : " + count);
-    }
-
-    public static int countEvenUsingInstanceVariable(int[] arr) {
-
-        for (int i = 0; i < arr.length; i++) {
-            if ((arr[i] % 2) == 0) {
-                instanceVariableCount++;
-            }
-
-        }
-        return instanceVariableCount;
-    }
-
-    public static int countEvenUsingIfElse(int[] arr, int args) {
-        int count;
-        count = args > 0 ? args : 0;
-        for (int i = 0; i < arr.length; i++) {
-            if ((arr[i] % 2) == 0) {
-                count++;
-            }
-
-        }
-        return count;
-    }
-}
@@ -1,24 +0,0 @@
-package com.baeldung.exception.variablemightnothavebeeninitialized;
-
-import org.junit.Test;
-
-import static org.junit.Assert.assertEquals;
-
-public class VariableMightNotHaveBeenInitializedUnitTest {
-
-    @Test
-    public void usingInstanceVariable_returnCount() {
-        int[] arr = new int[]{1, 2, 3, 4, 5, 6};
-        int value = VariableMightNotHaveBeenInitialized.countEvenUsingInstanceVariable(arr);
-
-        assertEquals(3, value);
-    }
-
-    @Test
-    public void usingArgumentsAndIfElse_returnCount() {
-        int[] arr = new int[]{1, 2, 3, 4, 5, 6};
-        int value = VariableMightNotHaveBeenInitialized.countEvenUsingIfElse(arr, 2);
-
-        assertEquals(5, value);
-    }
-}
@@ -0,0 +1,83 @@
+package com.baeldung.filetomap;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class FileToHashMap {
+
+    enum DupKeyOption {
+        OVERWRITE, DISCARD
+    }
+
+    public static Map<String, String> byBufferedReader(String filePath, DupKeyOption dupKeyOption) {
+        HashMap<String, String> map = new HashMap<>();
+        String line;
+        try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {
+            while ((line = reader.readLine()) != null) {
+                String[] keyValuePair = line.split(":", 2);
+                if (keyValuePair.length > 1) {
+                    String key = keyValuePair[0];
+                    String value = keyValuePair[1];
+                    if (DupKeyOption.OVERWRITE == dupKeyOption) {
+                        map.put(key, value);
+                    } else if (DupKeyOption.DISCARD == dupKeyOption) {
+                        map.putIfAbsent(key, value);
+                    }
+                } else {
+                    System.out.println("No Key:Value found in line, ignoring: " + line);
+                }
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return map;
+    }
+
+    public static Map<String, String> byStream(String filePath, DupKeyOption dupKeyOption) {
+        Map<String, String> map = new HashMap<>();
+        try (Stream<String> lines = Files.lines(Paths.get(filePath))) {
+            lines.filter(line -> line.contains(":"))
+                .forEach(line -> {
+                    String[] keyValuePair = line.split(":", 2);
+                    String key = keyValuePair[0];
+                    String value = keyValuePair[1];
+                    if (DupKeyOption.OVERWRITE == dupKeyOption) {
+                        map.put(key, value);
+                    } else if (DupKeyOption.DISCARD == dupKeyOption) {
+                        map.putIfAbsent(key, value);
+                    }
+                });
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return map;
+    }
+
+    public static Map<String, List<String>> aggregateByKeys(String filePath) {
+        Map<String, List<String>> map = new HashMap<>();
+        try (Stream<String> lines = Files.lines(Paths.get(filePath))) {
+            lines.filter(line -> line.contains(":"))
+                .forEach(line -> {
+                    String[] keyValuePair = line.split(":", 2);
+                    String key = keyValuePair[0];
+                    String value = keyValuePair[1];
+                    if (map.containsKey(key)) {
+                        map.get(key).add(value);
+                    } else {
+                        map.put(key, Stream.of(value).collect(Collectors.toList()));
+                    }
+                });
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return map;
+    }
+}
@@ -0,0 +1,66 @@
+package com.baeldung.filetomap;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.net.URISyntaxException;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class FileToHashMapUnitTest {
+
+    private String filePath;
+
+    private static final Map<String, String> EXPECTED_MAP_DISCARD = Stream.of(new String[][]{
+        {"title", "The Lord of the Rings: The Return of the King"},
+        {"director", "Peter Jackson"},
+        {"actor", "Sean Astin"}
+    }).collect(Collectors.toMap(data -> data[0], data -> data[1]));
+
+    private static final Map<String, String> EXPECTED_MAP_OVERWRITE = Stream.of(new String[][]{
+        {"title", "The Lord of the Rings: The Return of the King"},
+        {"director", "Peter Jackson"},
+        {"actor", "Ian McKellen"}
+    }).collect(Collectors.toMap(data -> data[0], data -> data[1]));
+
+    private static final Map<String, List<String>> EXPECTED_MAP_AGGREGATE = Stream.of(new String[][]{
+        {"title", "The Lord of the Rings: The Return of the King"},
+        {"director", "Peter Jackson"},
+        {"actor", "Sean Astin", "Ian McKellen"}
+    }).collect(Collectors.toMap(arr -> arr[0], arr -> Arrays.asList(Arrays.copyOfRange(arr, 1, arr.length))));
+
+    @Before
+    public void setPath() throws URISyntaxException {
+        if (filePath == null) {
+            filePath = Paths.get(ClassLoader.getSystemResource("filetomap/theLordOfRings.txt").toURI()).toString();
+        }
+    }
+
+    @Test
+    public void givenInputFile_whenInvokeByBufferedReaderPriorToJava8_shouldGetExpectedMap() {
+        Map<String, String> mapOverwrite = FileToHashMap.byBufferedReader(filePath, FileToHashMap.DupKeyOption.OVERWRITE);
+        Map<String, String> mapDiscard = FileToHashMap.byBufferedReader(filePath, FileToHashMap.DupKeyOption.DISCARD);
+        assertThat(mapOverwrite).isEqualTo(EXPECTED_MAP_OVERWRITE);
+        assertThat(mapDiscard).isEqualTo(EXPECTED_MAP_DISCARD);
+    }
+
+    @Test
+    public void givenInputFile_whenInvokeByStream_shouldGetExpectedMap() {
+        Map<String, String> mapOverwrite = FileToHashMap.byStream(filePath, FileToHashMap.DupKeyOption.OVERWRITE);
+        Map<String, String> mapDiscard = FileToHashMap.byStream(filePath, FileToHashMap.DupKeyOption.DISCARD);
+        assertThat(mapOverwrite).isEqualTo(EXPECTED_MAP_OVERWRITE);
+        assertThat(mapDiscard).isEqualTo(EXPECTED_MAP_DISCARD);
+    }
+
+    @Test
+    public void givenInputFile_whenInvokeAggregateByKeys_shouldGetExpectedMap() {
+        Map<String, List<String>> mapAgg = FileToHashMap.aggregateByKeys(filePath);
+        assertThat(mapAgg).isEqualTo(EXPECTED_MAP_AGGREGATE);
+    }
+}
@@ -0,0 +1,6 @@
+title:The Lord of the Rings: The Return of the King
+director:Peter Jackson
+actor:Sean Astin
+actor:Ian McKellen
+Gandalf and Aragorn lead the World of Men against Sauron's
+army to draw his gaze from Frodo and Sam as they approach Mount Doom with the One Ring.
@@ -7,3 +7,4 @@
 - [Dockerfile Strategies for Git](https://www.baeldung.com/ops/dockerfile-git-strategies)
 - [How to Get Docker-Compose to Always Use the Latest Image](https://www.baeldung.com/ops/docker-compose-latest-image)
 - [How to Include Files Outside of Docker’s Build Context](https://www.baeldung.com/ops/docker-include-files-outside-build-context)
+- [Caching Maven Dependencies with Docker](https://www.baeldung.com/ops/docker-cache-maven-dependencies)
@@ -12,8 +12,24 @@
        <groupId>com.baeldung</groupId>
        <artifactId>parent-modules</artifactId>
        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
    </parent>

+    <repositories>
+        <repository>
+            <id>jitpack.io</id>
+            <url>https://jitpack.io</url>
+        </repository>
+        <repository>
+            <snapshots>
+                <enabled>false</enabled>
+            </snapshots>
+            <id>central</id>
+            <name>Central Repository</name>
+            <url>https://repo.maven.apache.org/maven2</url>
+        </repository>
+    </repositories>
+
    <dependencies>
        <dependency>
            <groupId>com.graphql-java</groupId>
@@ -25,11 +41,114 @@
            <artifactId>ratpack-core</artifactId>
            <version>${ratpack-core.version}</version>
        </dependency>
+        <dependency>
+            <groupId>com.github.americanexpress.nodes</groupId>
+            <artifactId>nodes</artifactId>
+            <version>0.5.0</version>
+        </dependency>
+        <dependency>
+            <groupId>com.graphql-java</groupId>
+            <artifactId>graphql-java</artifactId>
+            <version>9.2</version>
+        </dependency>
+        <dependency>
+            <groupId>com.graphql-java</groupId>
+            <artifactId>graphql-java-tools</artifactId>
+            <version>5.2.4</version>
+        </dependency>
+        <dependency>
+            <groupId>com.graphql-java</groupId>
+            <artifactId>graphql-java-servlet</artifactId>
+            <version>6.1.3</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.servlet</groupId>
+            <artifactId>javax.servlet-api</artifactId>
+            <version>3.0.1</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>3.12.0</version>
+        </dependency>
+        <dependency>
+            <groupId>org.mock-server</groupId>
+            <artifactId>mockserver-netty</artifactId>
+            <version>5.11.2</version>
+        </dependency>
+        <dependency>
+            <groupId>org.mock-server</groupId>
+            <artifactId>mockserver-client-java</artifactId>
+            <version>5.11.2</version>
+        </dependency>
+        <dependency>
+            <groupId>com.graphql-java-generator</groupId>
+            <artifactId>graphql-java-runtime</artifactId>
+            <version>${graphql.java.generator.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>5.8.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>3.22.0</version>
+            <scope>test</scope>
+        </dependency>
    </dependencies>

+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${maven.compiler.source}</source>
+                    <target>${maven.compiler.target}</target>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.eclipse.jetty</groupId>
+                <artifactId>jetty-maven-plugin</artifactId>
+                <version>10.0.7</version>
+            </plugin>
+            <plugin>
+                <artifactId>maven-war-plugin</artifactId>
+                <version>3.1.0</version>
+            </plugin>
+            <plugin>
+                <groupId>com.graphql-java-generator</groupId>
+                <artifactId>graphql-maven-plugin</artifactId>
+                <version>${graphql.java.generator.version}</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>generateClientCode</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <packageName>com.baeldung.graphql.generated</packageName>
+                    <copyRuntimeSources>false</copyRuntimeSources>
+                    <generateDeprecatedRequestResponse>false</generateDeprecatedRequestResponse>
+                    <separateUtilityClasses>true</separateUtilityClasses>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
    <properties>
        <graphql-java-annotations.version>3.0.3</graphql-java-annotations.version>
        <ratpack-core.version>1.4.6</ratpack-core.version>
+        <maven-compiler-plugin.version>3.1</maven-compiler-plugin.version>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+        <graphql.java.generator.version>1.18</graphql.java.generator.version>
    </properties>

 </project>
@@ -0,0 +1,24 @@
+package com.baeldung.graphql.clients;
+
+import com.baeldung.graphql.data.Data;
+import io.aexp.nodes.graphql.GraphQLRequestEntity;
+import io.aexp.nodes.graphql.GraphQLResponseEntity;
+import io.aexp.nodes.graphql.GraphQLTemplate;
+import org.apache.commons.lang3.StringUtils;
+
+import java.io.IOException;
+
+public class AmericanExpressNodes {
+
+    public static GraphQLResponseEntity<Data> callGraphQLService(String url, String query) throws IOException {
+        GraphQLTemplate graphQLTemplate = new GraphQLTemplate();
+
+        GraphQLRequestEntity requestEntity = GraphQLRequestEntity.Builder()
+          .url(StringUtils.join(url, "?query=", query))
+          .request(Data.class)
+          .build();
+
+        return graphQLTemplate.query(requestEntity, Data.class);
+    }
+
+}
@@ -0,0 +1,25 @@
+package com.baeldung.graphql.clients;
+
+import org.apache.http.HttpResponse;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.utils.URIBuilder;
+import org.apache.http.impl.client.HttpClientBuilder;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+
+public class ApacheHttpClient {
+
+    public static HttpResponse callGraphQLService(String url, String query) throws URISyntaxException, IOException {
+        HttpClient client = HttpClientBuilder.create().build();
+        HttpGet request = new HttpGet(url);
+        URI uri = new URIBuilder(request.getURI())
+          .addParameter("query", query)
+          .build();
+        request.setURI(uri);
+        return client.execute(request);
+    }
+
+}
@@ -0,0 +1,31 @@
+package com.baeldung.graphql.data;
+
+import org.apache.commons.lang3.StringUtils;
+
+public class Author {
+
+    private String name;
+    private String surname;
+
+    public Author() {
+
+    }
+
+    public Author(String name, String surname) {
+        this.name = name;
+        this.surname = surname;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public String getFullName() {
+        return StringUtils.join(getName(), " ", getSurname());
+    }
+
+}
@@ -0,0 +1,25 @@
+package com.baeldung.graphql.data;
+
+public class Book {
+
+    private String title;
+    private Author author;
+
+    public Book() {
+
+    }
+
+    public Book(String title, Author author) {
+        this.title = title;
+        this.author = author;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public Author getAuthor() {
+        return author;
+    }
+
+}
@@ -0,0 +1,19 @@
+package com.baeldung.graphql.data;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class BookRepository {
+
+    private static final List<Book> books = Stream.of(
+            new Book("Title 1", new Author("Pero", "Peric")),
+            new Book("Title 2", new Author("Marko", "Maric"))
+        ).collect(Collectors.toList());
+
+    public List<Book> getAllBooks() {
+        return Collections.unmodifiableList(books);
+    }
+
+}
@@ -0,0 +1,22 @@
+package com.baeldung.graphql.data;
+
+import java.util.Collections;
+import java.util.List;
+
+public class Data {
+
+    private List<Book> allBooks;
+
+    public Data() {
+
+    }
+
+    public Data(List<Book> allBooks) {
+        this.allBooks = allBooks;
+    }
+
+    public List<Book> getAllBooks() {
+        return Collections.unmodifiableList(allBooks);
+    }
+
+}
@@ -0,0 +1,19 @@
+package com.baeldung.graphql.data;
+
+public class Response {
+
+    private Data data;
+
+    public Response() {
+
+    }
+
+    public Response(Data data) {
+        this.data = data;
+    }
+
+    public Data getData() {
+        return data;
+    }
+
+}
@@ -0,0 +1,36 @@
+package com.baeldung.graphql.server;
+
+import com.baeldung.graphql.data.BookRepository;
+import com.coxautodev.graphql.tools.SchemaParser;
+import graphql.schema.GraphQLSchema;
+import graphql.servlet.SimpleGraphQLHttpServlet;
+
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+@WebServlet(urlPatterns = "/graphql")
+public class GraphQLEndpoint extends HttpServlet {
+
+    private SimpleGraphQLHttpServlet graphQLServlet;
+
+    @Override
+    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        graphQLServlet.service(req, resp);
+    }
+
+    @Override
+    public void init() {
+        GraphQLSchema schema = SchemaParser.newParser()
+          .resolvers(new GraphQLQuery(new BookRepository()))
+          .file("schema.graphqls")
+          .build()
+          .makeExecutableSchema();
+        graphQLServlet = SimpleGraphQLHttpServlet
+          .newBuilder(schema)
+          .build();
+    }
+}
@@ -0,0 +1,21 @@
+package com.baeldung.graphql.server;
+
+import com.baeldung.graphql.data.Book;
+import com.baeldung.graphql.data.BookRepository;
+import com.coxautodev.graphql.tools.GraphQLQueryResolver;
+
+import java.util.List;
+
+public class GraphQLQuery implements GraphQLQueryResolver {
+
+    private final BookRepository repository;
+
+    public GraphQLQuery(BookRepository repository) {
+        this.repository = repository;
+    }
+
+    public List<Book> allBooks() {
+        return repository.getAllBooks();
+    }
+
+}
@@ -0,0 +1,17 @@
+type Book {
+  title: String!
+  author: Author
+}
+
+type Author {
+  name: String!
+  surname: String!
+}
+
+type Query {
+  allBooks: [Book]
+}
+
+schema {
+  query: Query
+}
@@ -0,0 +1,85 @@
+package com.baeldung.graphql;
+
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.mockserver.client.MockServerClient;
+import org.mockserver.integration.ClientAndServer;
+import org.mockserver.model.HttpStatusCode;
+
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.URISyntaxException;
+
+import static org.mockserver.integration.ClientAndServer.startClientAndServer;
+import static org.mockserver.matchers.Times.exactly;
+import static org.mockserver.model.HttpRequest.request;
+import static org.mockserver.model.HttpResponse.response;
+
+public class GraphQLMockServer {
+
+    public static ClientAndServer mockServer;
+    public static String serviceUrl;
+
+    private static int serverPort;
+
+    public static final String SERVER_ADDRESS = "127.0.0.1";
+    public static final String HTTP_GET_POST = "GET";
+    public static final String PATH = "/graphql";
+
+    @BeforeAll
+    static void startServer() throws IOException, URISyntaxException {
+        serverPort = getFreePort();
+        serviceUrl = "http://" + SERVER_ADDRESS + ":" + serverPort + PATH;
+        mockServer = startClientAndServer(serverPort);
+        mockAllBooksTitleRequest();
+        mockAllBooksTitleAuthorRequest();
+    }
+
+    @AfterAll
+    static void stopServer() {
+        mockServer.stop();
+    }
+
+    private static void mockAllBooksTitleAuthorRequest() {
+        String requestQuery = "{allBooks{title,author{name,surname}}}";
+        String responseJson = "{\"data\":{\"allBooks\":[{\"title\":\"Title 1\",\"author\":{\"name\":\"Pero\",\"surname\":\"Peric\"}},{\"title\":\"Title 2\",\"author\":{\"name\":\"Marko\",\"surname\":\"Maric\"}}]}}";
+
+        new MockServerClient(SERVER_ADDRESS, serverPort)
+          .when(
+            request()
+              .withPath(PATH)
+              .withQueryStringParameter("query", requestQuery),
+            exactly(1)
+          )
+          .respond(
+            response()
+              .withStatusCode(HttpStatusCode.OK_200.code())
+              .withBody(responseJson)
+          );
+    }
+
+    private static void mockAllBooksTitleRequest() {
+        String requestQuery = "{allBooks{title}}";
+        String responseJson = "{\"data\":{\"allBooks\":[{\"title\":\"Title 1\"},{\"title\":\"Title 2\"}]}}";
+
+        new MockServerClient(SERVER_ADDRESS, serverPort)
+          .when(
+            request()
+              .withPath(PATH)
+              .withQueryStringParameter("query", requestQuery),
+            exactly(1)
+          )
+          .respond(
+            response()
+              .withStatusCode(HttpStatusCode.OK_200.code())
+              .withBody(responseJson)
+          );
+    }
+
+    private static int getFreePort () throws IOException {
+        try (ServerSocket serverSocket = new ServerSocket(0)) {
+            return serverSocket.getLocalPort();
+        }
+    }
+
+}
@@ -0,0 +1,39 @@
+package com.baeldung.graphql.clients;
+
+import com.baeldung.graphql.GraphQLMockServer;
+import com.baeldung.graphql.data.Data;
+import io.aexp.nodes.graphql.GraphQLResponseEntity;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertAll;
+
+class AmericanExpressNodesUnitTest extends GraphQLMockServer {
+
+    @Test
+    void givenGraphQLEndpoint_whenRequestingAllBooksWithTitle_thenExpectedJsonIsReturned() throws IOException {
+        GraphQLResponseEntity<Data> responseEntity = AmericanExpressNodes.callGraphQLService(serviceUrl, "{allBooks{title}}");
+
+        assertAll(
+          () -> assertThat(responseEntity.getResponse().getAllBooks()).hasSize(2),
+          () -> assertThat(responseEntity.getResponse().getAllBooks().get(0).getTitle()).isEqualTo("Title 1"),
+          () -> assertThat(responseEntity.getResponse().getAllBooks().get(1).getTitle()).isEqualTo("Title 2")
+        );
+    }
+
+    @Test
+    void givenGraphQLEndpoint_whenRequestingAllBooksWithTitleAndAuthor_thenExpectedJsonIsReturned() throws IOException {
+        GraphQLResponseEntity<Data> responseEntity = AmericanExpressNodes.callGraphQLService(serviceUrl, "{allBooks{title,author{name,surname}}}");
+
+        assertAll(
+          () -> assertThat(responseEntity.getResponse().getAllBooks()).hasSize(2),
+          () -> assertThat(responseEntity.getResponse().getAllBooks().get(0).getTitle()).isEqualTo("Title 1"),
+          () -> assertThat(responseEntity.getResponse().getAllBooks().get(0).getAuthor().getFullName()).isEqualTo("Pero Peric"),
+          () -> assertThat(responseEntity.getResponse().getAllBooks().get(1).getTitle()).isEqualTo("Title 2"),
+          () -> assertThat(responseEntity.getResponse().getAllBooks().get(1).getAuthor().getFullName()).isEqualTo("Marko Maric")
+        );
+    }
+
+}
@@ -0,0 +1,49 @@
+package com.baeldung.graphql.clients;
+
+import com.baeldung.graphql.GraphQLMockServer;
+import com.baeldung.graphql.data.Response;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.commons.io.IOUtils;
+import org.apache.http.HttpResponse;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.charset.StandardCharsets;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertAll;
+
+class ApacheHttpClientUnitTest extends GraphQLMockServer {
+
+    private static final ObjectMapper objectMapper = new ObjectMapper();
+
+    @Test
+    void givenGraphQLEndpoint_whenRequestingAllBooksWithTitle_thenExpectedJsonIsReturned() throws IOException, URISyntaxException {
+        HttpResponse httpResponse = ApacheHttpClient.callGraphQLService(serviceUrl, "{allBooks{title}}");
+        String actualResponse = IOUtils.toString(httpResponse.getEntity().getContent(), StandardCharsets.UTF_8.name());
+        Response parsedResponse = objectMapper.readValue(actualResponse, Response.class);
+
+        assertAll(
+            () -> assertThat(parsedResponse.getData().getAllBooks()).hasSize(2),
+            () -> assertThat(parsedResponse.getData().getAllBooks().get(0).getTitle()).isEqualTo("Title 1"),
+            () -> assertThat(parsedResponse.getData().getAllBooks().get(1).getTitle()).isEqualTo("Title 2")
+        );
+    }
+
+    @Test
+    void givenGraphQLEndpoint_whenRequestingAllBooksWithTitleAndAuthor_thenExpectedJsonIsReturned() throws IOException, URISyntaxException {
+        HttpResponse httpResponse = ApacheHttpClient.callGraphQLService(serviceUrl, "{allBooks{title,author{name,surname}}}");
+        String actualResponse = IOUtils.toString(httpResponse.getEntity().getContent(), StandardCharsets.UTF_8.name());
+        Response parsedResponse = objectMapper.readValue(actualResponse, Response.class);
+
+        assertAll(
+          () -> assertThat(parsedResponse.getData().getAllBooks()).hasSize(2),
+          () -> assertThat(parsedResponse.getData().getAllBooks().get(0).getTitle()).isEqualTo("Title 1"),
+          () -> assertThat(parsedResponse.getData().getAllBooks().get(0).getAuthor().getFullName()).isEqualTo("Pero Peric"),
+          () -> assertThat(parsedResponse.getData().getAllBooks().get(1).getTitle()).isEqualTo("Title 2"),
+          () -> assertThat(parsedResponse.getData().getAllBooks().get(1).getAuthor().getFullName()).isEqualTo("Marko Maric")
+        );
+    }
+
+}
@@ -3,3 +3,4 @@
 This module contains articles about Servlets.

 ### Relevant Articles:
+- [Check if a User Is Logged-in With Servlets and JSP](https://www.baeldung.com/servlets-jsp-check-user-login)
@@ -0,0 +1,56 @@
+package com.baeldung.lombok.tostring;
+
+import lombok.ToString;
+
+@ToString
+public class Account {
+
+    private String name;
+
+    // render this field before any others (the highest ranked)
+    @ToString.Include(rank = 1)
+    private String id;
+
+    @ToString.Exclude
+    private String accountNumber;
+
+    // automatically excluded
+    private String $ignored;
+
+    @ToString.Include
+    String description() {
+        return "Account description";
+    }
+
+    public String getAccountNumber() {
+        return accountNumber;
+    }
+
+    public void setAccountNumber(String accountNumber) {
+        this.accountNumber = accountNumber;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String get$ignored() {
+        return $ignored;
+    }
+
+    public void set$ignored(String value) {
+        this.$ignored = value;
+    }
+}
@@ -0,0 +1,9 @@
+package com.baeldung.lombok.tostring;
+
+import lombok.ToString;
+
+@ToString
+public enum AccountType {
+    CHECKING,
+    SAVING
+}
@@ -0,0 +1,27 @@
+package com.baeldung.lombok.tostring;
+
+import lombok.ToString;
+
+@ToString
+public class RewardAccount extends Account {
+
+    private String rewardAccountId;
+
+    private Object[] relatedAccounts;
+
+    public String getRewardAccountId() {
+        return rewardAccountId;
+    }
+
+    public void setRewardAccountId(String rewardAccountId) {
+        this.rewardAccountId = rewardAccountId;
+    }
+
+    public Object[] getRelatedAccounts() {
+        return relatedAccounts;
+    }
+
+    public void setRelatedAccounts(Object[] relatedAccounts) {
+        this.relatedAccounts = relatedAccounts;
+    }
+}
--- a/Show More
+++ b/Show More