eugenp · anastasiosioannidis · Jun 22, 2025 · Jun 18, 2025 · Jun 18, 2025 · Jun 19, 2025
diff --git a/...a-modules/core-java-lang-oop-methods/src/main/java/com/baeldung/hashcode/Application.java b/...a-modules/core-java-lang-oop-methods/src/main/java/com/baeldung/hashcode/Application.java
@@ -0,0 +1,23 @@
+package com.baeldung.hashcode;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import com.baeldung.hashcode.standard.User;
+
+public class Application {
+
+    public static void main(String[] args) {
+        Map<User, User> users = new HashMap<>();
+        User user1 = new User(1L, "John", "john@domain.com");
+        User user2 = new User(2L, "Jennifer", "jennifer@domain.com");
+        User user3 = new User(3L, "Mary", "mary@domain.com");
+
+        users.put(user1, user1);
+        users.put(user2, user2);
+        users.put(user3, user3);
+        if (users.containsKey(user1)) {
+            System.out.print("User found in the collection");
+        }
+    }
+}
diff --git a/...g-data-jpa-query/src/main/java/com/baeldung/boot/passenger/CustomPassengerRepository.java b/...g-data-jpa-query/src/main/java/com/baeldung/boot/passenger/CustomPassengerRepository.java
@@ -0,0 +1,8 @@
+package com.baeldung.boot.passenger;
+
+import java.util.List;
+
+interface CustomPassengerRepository {
+
+    List<Passenger> findOrderedBySeatNumberLimitedTo(int limit);
+}
diff --git a/...ce-modules/spring-data-jpa-query/src/main/java/com/baeldung/boot/passenger/Passenger.java b/...ce-modules/spring-data-jpa-query/src/main/java/com/baeldung/boot/passenger/Passenger.java
@@ -0,0 +1,83 @@
+package com.baeldung.boot.passenger;
+
+import java.util.Objects;
+
+import jakarta.persistence.Basic;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+
+@Entity
+class Passenger {
+
+    @Id
+    @GeneratedValue
+    @Column(nullable = false)
+    private Long id;
+
+    @Basic(optional = false)
+    @Column(nullable = false)
+    private String firstName;
+
+    @Basic(optional = false)
+    @Column(nullable = false)
+    private String lastName;
+
+    @Basic(optional = false)
+    @Column(nullable = false)
+    private Integer seatNumber;
+
+    private Passenger(String firstName, String lastName, Integer seatNumber) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.seatNumber = seatNumber;
+    }
+
+    static Passenger from(String firstName, String lastName, Integer seatNumber) {
+        return new Passenger(firstName, lastName, seatNumber);
+    }
+
+    @Override
+    public boolean equals(Object object) {
+        if (this == object)
+            return true;
+        if (object == null || getClass() != object.getClass())
+            return false;
+        Passenger passenger = (Passenger) object;
+        return getSeatNumber() == passenger.getSeatNumber() && Objects.equals(getFirstName(), passenger.getFirstName())
+          && Objects.equals(getLastName(), passenger.getLastName());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getFirstName(), getLastName(), getSeatNumber());
+    }
+
+    @Override
+    public String toString() {
+        final StringBuilder toStringBuilder = new StringBuilder(getClass().getSimpleName());
+        toStringBuilder.append("{ id=").append(id);
+        toStringBuilder.append(", firstName='").append(firstName).append('\'');
+        toStringBuilder.append(", lastName='").append(lastName).append('\'');
+        toStringBuilder.append(", seatNumber=").append(seatNumber);
+        toStringBuilder.append('}');
+        return toStringBuilder.toString();
+    }
+
+    Long getId() {
+        return id;
+    }
+
+    String getFirstName() {
+        return firstName;
+    }
+
+    String getLastName() {
+        return lastName;
+    }
+
+    Integer getSeatNumber() {
+        return seatNumber;
+    }
+}
diff --git a/.../spring-data-jpa-query/src/main/java/com/baeldung/boot/passenger/PassengerRepository.java b/.../spring-data-jpa-query/src/main/java/com/baeldung/boot/passenger/PassengerRepository.java
@@ -0,0 +1,14 @@
+package com.baeldung.boot.passenger;
+
+import java.util.List;
+
+import org.springframework.data.domain.Sort;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+interface PassengerRepository extends JpaRepository<Passenger, Long>, CustomPassengerRepository {
+
+    Passenger findFirstByOrderBySeatNumberAsc();
+
+    Passenger findTopByOrderBySeatNumberAsc();
+
+}
diff --git a/...ing-data-jpa-query/src/main/java/com/baeldung/boot/passenger/PassengerRepositoryImpl.java b/...ing-data-jpa-query/src/main/java/com/baeldung/boot/passenger/PassengerRepositoryImpl.java
@@ -0,0 +1,21 @@
+package com.baeldung.boot.passenger;
+
+import java.util.List;
+
+import org.springframework.stereotype.Repository;
+
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.PersistenceContext;
+
+@Repository
+class PassengerRepositoryImpl implements CustomPassengerRepository {
+
+    @PersistenceContext
+    private EntityManager entityManager;
+
+    @Override
+    public List<Passenger> findOrderedBySeatNumberLimitedTo(int limit) {
+        return entityManager.createQuery("SELECT p FROM Passenger p ORDER BY p.seatNumber",
+          Passenger.class).setMaxResults(limit).getResultList();
+    }
+}
diff --git a/spring-boot-modules/spring-boot-3/pom.xml b/spring-boot-modules/spring-boot-3/pom.xml
@@ -166,9 +166,6 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <configuration>
-                    <compilerArgs>--enable-preview</compilerArgs>
-                </configuration>
             </plugin>
         </plugins>
     </build>

diff --git a/...nt/InterceptingClientHttpRequestTest.java → ...lient/InterceptingClientHttpUnitTest.java b/...nt/InterceptingClientHttpRequestTest.java → ...lient/InterceptingClientHttpUnitTest.java
@@ -1,18 +1,11 @@
 package com.baeldung.restclient;
 
-
-import org.junit.jupiter.api.Test;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 
-import org.springframework.http.HttpMethod;
-import org.springframework.http.HttpRequest;
+import org.junit.jupiter.api.Test;
 import org.springframework.http.client.ClientHttpRequestInterceptor;
-import org.springframework.http.client.ClientHttpResponse;
-import org.springframework.http.client.ClientHttpRequest;
-import org.springframework.http.client.support.HttpRequestWrapper;
-
 
-class InterceptingClientHttpRequestTest {
+class InterceptingClientHttpUnitTest {
 
     @Test
     void updateRequestAttribute() throws Exception {

diff --git a/...-web-modules/spring-mvc-basics-2/src/main/java/com/baeldung/spring/mail/EmailService.java b/...-web-modules/spring-mvc-basics-2/src/main/java/com/baeldung/spring/mail/EmailService.java
@@ -33,6 +33,4 @@ void sendMessageUsingFreemarkerTemplate(String to,
                                             Map<String, Object> templateModel)
             throws IOException, TemplateException, MessagingException;
 
-    void sendMessageWithInputStreamAttachment(
-        String to, String subject, String text, String attachmentName, InputStream inputStream);
 }
diff --git a/...-modules/spring-mvc-basics-2/src/main/java/com/baeldung/spring/mail/EmailServiceImpl.java b/...-modules/spring-mvc-basics-2/src/main/java/com/baeldung/spring/mail/EmailServiceImpl.java
@@ -132,26 +132,4 @@ private void sendHtmlMessage(String to, String subject, String htmlBody) throws
         emailSender.send(message);
     }
 
-    @Override
-    public void sendMessageWithInputStreamAttachment(
-        String to, String subject, String text, String attachmentName, InputStream attachmentStream) {
-
-        try {
-            MimeMessage message = emailSender.createMimeMessage();
-            MimeMessageHelper helper = new MimeMessageHelper(message, true);
-
-            helper.setFrom(NOREPLY_ADDRESS);
-            helper.setTo(to);
-            helper.setSubject(subject);
-            helper.setText(text);
-
-            // Add the attachment from InputStream
-            helper.addAttachment(attachmentName, new InputStreamResource(attachmentStream));
-
-            emailSender.send(message);
-        } catch (MessagingException e) {
-            e.printStackTrace();
-        }
-    }
-
 }
diff --git a/...ng-web-modules/spring-mvc-basics/src/main/java/com/baeldung/spring/mail/EmailService.java b/...ng-web-modules/spring-mvc-basics/src/main/java/com/baeldung/spring/mail/EmailService.java
@@ -1,6 +1,7 @@
 package com.baeldung.spring.mail;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.Map;
 
 import jakarta.mail.MessagingException;
@@ -17,4 +18,7 @@ void sendMessageWithAttachment(String to,
         String subject,
         String text,
         String pathToAttachment);
+
+    void sendMessageWithInputStreamAttachment(
+        String to, String subject, String text, String attachmentName, InputStream inputStream);
 }
diff --git a/...eb-modules/spring-mvc-basics/src/main/java/com/baeldung/spring/mail/EmailServiceImpl.java b/...eb-modules/spring-mvc-basics/src/main/java/com/baeldung/spring/mail/EmailServiceImpl.java
@@ -1,10 +1,12 @@
 package com.baeldung.spring.mail;
 
 import java.io.File;
+import java.io.InputStream;
 
 import org.springframework.beans.factory.annotation.Autowired;
 
 import org.springframework.core.io.FileSystemResource;
+import org.springframework.core.io.InputStreamResource;
 import org.springframework.mail.MailException;
 import org.springframework.mail.SimpleMailMessage;
 import org.springframework.mail.javamail.JavaMailSender;
@@ -66,5 +68,26 @@ public void sendMessageWithAttachment(String to,
         }
     }
 
+    @Override
+    public void sendMessageWithInputStreamAttachment(
+        String to, String subject, String text, String attachmentName, InputStream attachmentStream) {
+
+        try {
+            MimeMessage message = emailSender.createMimeMessage();
+            MimeMessageHelper helper = new MimeMessageHelper(message, true);
+
+            helper.setFrom(NOREPLY_ADDRESS);
+            helper.setTo(to);
+            helper.setSubject(subject);
+            helper.setText(text);
+
+            // Add the attachment from InputStream
+            helper.addAttachment(attachmentName, new InputStreamResource(attachmentStream));
+
+            emailSender.send(message);
+        } catch (MessagingException e) {
+            e.printStackTrace();
+        }
+    }
 
 }