diff --git a/src/main/java/core/basesyntax/dao/impl/CommentDaoImpl.java b/src/main/java/core/basesyntax/dao/impl/CommentDaoImpl.java
index 5176c951f..891a55621 100644
--- a/src/main/java/core/basesyntax/dao/impl/CommentDaoImpl.java
+++ b/src/main/java/core/basesyntax/dao/impl/CommentDaoImpl.java
@@ -3,7 +3,9 @@
 import core.basesyntax.dao.CommentDao;
 import core.basesyntax.model.Comment;
 import java.util.List;
+import org.hibernate.Session;
 import org.hibernate.SessionFactory;
+import org.hibernate.Transaction;
 
 public class CommentDaoImpl extends AbstractDao implements CommentDao {
     public CommentDaoImpl(SessionFactory sessionFactory) {
@@ -12,21 +14,65 @@ public CommentDaoImpl(SessionFactory sessionFactory) {
 
     @Override
     public Comment create(Comment entity) {
-        return null;
+        Session session = null;
+        Transaction transaction = null;
+        try {
+            session = factory.openSession();
+            transaction = session.beginTransaction();
+            session.persist(entity);
+            transaction.commit();
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+            throw new RuntimeException("Can't save comment '" + entity.getContent()
+                    + "' to DB.", e);
+        } finally {
+            if (session != null) {
+                session.close();
+            }
+        }
+        return entity;
     }
 
     @Override
     public Comment get(Long id) {
-        return null;
+        try (Session session = factory.openSession()) {
+            return session.get(Comment.class, id);
+        } catch (Exception e) {
+            throw new RuntimeException("Can't get comment from DB with id=" + id, e);
+        }
     }
 
     @Override
     public List<Comment> getAll() {
-        return null;
+        try (Session session = factory.openSession()) {
+            String hql = "FROM Comment";
+            return session.createQuery(hql, Comment.class).getResultList();
+        } catch (Exception e) {
+            throw new RuntimeException("Can't get all comments from DB.", e);
+        }
     }
 
     @Override
     public void remove(Comment entity) {
-
+        Session session = null;
+        Transaction transaction = null;
+        try {
+            session = factory.openSession();
+            transaction = session.beginTransaction();
+            session.remove(entity);
+            transaction.commit();
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+            throw new RuntimeException("Can't delete comment '" + entity.getContent()
+                    + "' from DB.", e);
+        } finally {
+            if (session != null) {
+                session.close();
+            }
+        }
     }
 }
diff --git a/src/main/java/core/basesyntax/dao/impl/MessageDaoImpl.java b/src/main/java/core/basesyntax/dao/impl/MessageDaoImpl.java
index 9b899fa95..20879be45 100644
--- a/src/main/java/core/basesyntax/dao/impl/MessageDaoImpl.java
+++ b/src/main/java/core/basesyntax/dao/impl/MessageDaoImpl.java
@@ -3,7 +3,9 @@
 import core.basesyntax.dao.MessageDao;
 import core.basesyntax.model.Message;
 import java.util.List;
+import org.hibernate.Session;
 import org.hibernate.SessionFactory;
+import org.hibernate.Transaction;
 
 public class MessageDaoImpl extends AbstractDao implements MessageDao {
     public MessageDaoImpl(SessionFactory sessionFactory) {
@@ -12,21 +14,65 @@ public MessageDaoImpl(SessionFactory sessionFactory) {
 
     @Override
     public Message create(Message entity) {
-        return null;
+        Session session = null;
+        Transaction transaction = null;
+        try {
+            session = factory.openSession();
+            transaction = session.beginTransaction();
+            session.persist(entity);
+            transaction.commit();
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+            throw new RuntimeException("Can't save message '" + entity.getContent()
+                    + "' to DB.", e);
+        } finally {
+            if (session != null) {
+                session.close();
+            }
+        }
+        return entity;
     }
 
     @Override
     public Message get(Long id) {
-        return null;
+        try (Session session = factory.openSession()) {
+            return session.get(Message.class, id);
+        } catch (Exception e) {
+            throw new RuntimeException("Can't get message from DB with id=" + id, e);
+        }
     }
 
     @Override
     public List<Message> getAll() {
-        return null;
+        try (Session session = factory.openSession()) {
+            String hql = "FROM Message";
+            return session.createQuery(hql, Message.class).getResultList();
+        } catch (Exception e) {
+            throw new RuntimeException("Can't get all messages from DB.", e);
+        }
     }
 
     @Override
     public void remove(Message entity) {
-
+        Session session = null;
+        Transaction transaction = null;
+        try {
+            session = factory.openSession();
+            transaction = session.beginTransaction();
+            session.remove(entity);
+            transaction.commit();
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+            throw new RuntimeException("Can't delete message '" + entity.getContent()
+                    + "' from DB.", e);
+        } finally {
+            if (session != null) {
+                session.close();
+            }
+        }
     }
 }
diff --git a/src/main/java/core/basesyntax/dao/impl/MessageDetailsDaoImpl.java b/src/main/java/core/basesyntax/dao/impl/MessageDetailsDaoImpl.java
index fb96d35aa..5f62e5e13 100644
--- a/src/main/java/core/basesyntax/dao/impl/MessageDetailsDaoImpl.java
+++ b/src/main/java/core/basesyntax/dao/impl/MessageDetailsDaoImpl.java
@@ -2,7 +2,9 @@
 
 import core.basesyntax.dao.MessageDetailsDao;
 import core.basesyntax.model.MessageDetails;
+import org.hibernate.Session;
 import org.hibernate.SessionFactory;
+import org.hibernate.Transaction;
 
 public class MessageDetailsDaoImpl extends AbstractDao implements MessageDetailsDao {
     public MessageDetailsDaoImpl(SessionFactory sessionFactory) {
@@ -11,11 +13,33 @@ public MessageDetailsDaoImpl(SessionFactory sessionFactory) {
 
     @Override
     public MessageDetails create(MessageDetails entity) {
-        return null;
+        Session session = null;
+        Transaction transaction = null;
+        try {
+            session = factory.openSession();
+            transaction = session.beginTransaction();
+            session.persist(entity);
+            transaction.commit();
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+            throw new RuntimeException("Can't save message details '" + entity.getSender()
+                    + " " + entity.getSentTime() + "' to DB.", e);
+        } finally {
+            if (session != null) {
+                session.close();
+            }
+        }
+        return entity;
     }
 
     @Override
     public MessageDetails get(Long id) {
-        return null;
+        try (Session session = factory.openSession()) {
+            return session.get(MessageDetails.class, id);
+        } catch (Exception e) {
+            throw new RuntimeException("Can't get message details from DB with id=" + id, e);
+        }
     }
 }
diff --git a/src/main/java/core/basesyntax/dao/impl/SmileDaoImpl.java b/src/main/java/core/basesyntax/dao/impl/SmileDaoImpl.java
index 559248cda..5a83ff90b 100644
--- a/src/main/java/core/basesyntax/dao/impl/SmileDaoImpl.java
+++ b/src/main/java/core/basesyntax/dao/impl/SmileDaoImpl.java
@@ -3,7 +3,9 @@
 import core.basesyntax.dao.SmileDao;
 import core.basesyntax.model.Smile;
 import java.util.List;
+import org.hibernate.Session;
 import org.hibernate.SessionFactory;
+import org.hibernate.Transaction;
 
 public class SmileDaoImpl extends AbstractDao implements SmileDao {
     public SmileDaoImpl(SessionFactory sessionFactory) {
@@ -12,16 +14,43 @@ public SmileDaoImpl(SessionFactory sessionFactory) {
 
     @Override
     public Smile create(Smile entity) {
-        return null;
+        Session session = null;
+        Transaction transaction = null;
+        try {
+            session = factory.openSession();
+            transaction = session.beginTransaction();
+            session.persist(entity);
+            transaction.commit();
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+            throw new RuntimeException("Can't save smile '" + entity.getValue()
+                    + "' to DB.", e);
+        } finally {
+            if (session != null) {
+                session.close();
+            }
+        }
+        return entity;
     }
 
     @Override
     public Smile get(Long id) {
-        return null;
+        try (Session session = factory.openSession()) {
+            return session.get(Smile.class, id);
+        } catch (Exception e) {
+            throw new RuntimeException("Can't get smile from DB with id=" + id, e);
+        }
     }
 
     @Override
     public List<Smile> getAll() {
-        return null;
+        try (Session session = factory.openSession()) {
+            String hql = "FROM Smile";
+            return session.createQuery(hql, Smile.class).getResultList();
+        } catch (Exception e) {
+            throw new RuntimeException("Can't get all smiles from DB.", e);
+        }
     }
 }
diff --git a/src/main/java/core/basesyntax/dao/impl/UserDaoImpl.java b/src/main/java/core/basesyntax/dao/impl/UserDaoImpl.java
index 338d8248b..a51600f76 100644
--- a/src/main/java/core/basesyntax/dao/impl/UserDaoImpl.java
+++ b/src/main/java/core/basesyntax/dao/impl/UserDaoImpl.java
@@ -3,7 +3,9 @@
 import core.basesyntax.dao.UserDao;
 import core.basesyntax.model.User;
 import java.util.List;
+import org.hibernate.Session;
 import org.hibernate.SessionFactory;
+import org.hibernate.Transaction;
 
 public class UserDaoImpl extends AbstractDao implements UserDao {
     public UserDaoImpl(SessionFactory sessionFactory) {
@@ -12,21 +14,65 @@ public UserDaoImpl(SessionFactory sessionFactory) {
 
     @Override
     public User create(User entity) {
-        return null;
+        Session session = null;
+        Transaction transaction = null;
+        try {
+            session = factory.openSession();
+            transaction = session.beginTransaction();
+            session.persist(entity);
+            transaction.commit();
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+            throw new RuntimeException("Can't save user '" + entity.getUsername()
+                    + "' to DB.", e);
+        } finally {
+            if (session != null) {
+                session.close();
+            }
+        }
+        return entity;
     }
 
     @Override
     public User get(Long id) {
-        return null;
+        try (Session session = factory.openSession()) {
+            return session.get(User.class, id);
+        } catch (Exception e) {
+            throw new RuntimeException("Can't get user from DB with id=" + id, e);
+        }
     }
 
     @Override
     public List<User> getAll() {
-        return null;
+        try (Session session = factory.openSession()) {
+            String hql = "FROM User";
+            return session.createQuery(hql, User.class).getResultList();
+        } catch (Exception e) {
+            throw new RuntimeException("Can't get all users from DB.", e);
+        }
     }
 
     @Override
     public void remove(User entity) {
-
+        Session session = null;
+        Transaction transaction = null;
+        try {
+            session = factory.openSession();
+            transaction = session.beginTransaction();
+            session.remove(entity);
+            transaction.commit();
+        } catch (Exception e) {
+            if (transaction != null) {
+                transaction.rollback();
+            }
+            throw new RuntimeException("Can't delete user '" + entity.getUsername()
+                    + "' from DB.", e);
+        } finally {
+            if (session != null) {
+                session.close();
+            }
+        }
     }
 }
diff --git a/src/main/java/core/basesyntax/model/Comment.java b/src/main/java/core/basesyntax/model/Comment.java
index 9fba0c920..920d32934 100644
--- a/src/main/java/core/basesyntax/model/Comment.java
+++ b/src/main/java/core/basesyntax/model/Comment.java
@@ -1,15 +1,19 @@
 package core.basesyntax.model;
 
+import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
 import java.util.List;
 
+@Entity
 public class Comment {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
     private String content;
+    @OneToMany
     private List<Smile> smiles;
 
     public Long getId() {
diff --git a/src/main/java/core/basesyntax/model/Message.java b/src/main/java/core/basesyntax/model/Message.java
index 672b5d485..3f4d1340f 100644
--- a/src/main/java/core/basesyntax/model/Message.java
+++ b/src/main/java/core/basesyntax/model/Message.java
@@ -1,8 +1,19 @@
 package core.basesyntax.model;
 
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToOne;
+
+@Entity
 public class Message {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
     private String content;
+    @OneToOne(cascade = {CascadeType.PERSIST, CascadeType.REMOVE})
     private MessageDetails messageDetails;
 
     public Long getId() {
diff --git a/src/main/java/core/basesyntax/model/MessageDetails.java b/src/main/java/core/basesyntax/model/MessageDetails.java
index 185023dd5..d988e46f0 100644
--- a/src/main/java/core/basesyntax/model/MessageDetails.java
+++ b/src/main/java/core/basesyntax/model/MessageDetails.java
@@ -1,8 +1,15 @@
 package core.basesyntax.model;
 
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
 import java.time.LocalDateTime;
 
+@Entity
 public class MessageDetails {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
     private String sender;
     private LocalDateTime sentTime;
diff --git a/src/main/java/core/basesyntax/model/User.java b/src/main/java/core/basesyntax/model/User.java
index 0141eef00..b51baf73d 100644
--- a/src/main/java/core/basesyntax/model/User.java
+++ b/src/main/java/core/basesyntax/model/User.java
@@ -1,10 +1,21 @@
 package core.basesyntax.model;
 
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
 import java.util.List;
 
+@Entity
 public class User {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
     private String username;
+    @OneToMany(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
     private List<Comment> comments;
 
     public Long getId() {
diff --git a/src/main/resources/hibernate.cfg.xml b/src/main/resources/hibernate.cfg.xml
index cba4560a4..58e90f804 100644
--- a/src/main/resources/hibernate.cfg.xml
+++ b/src/main/resources/hibernate.cfg.xml
@@ -13,6 +13,10 @@
         <property name="show_sql">true</property>
         <property name="hbm2ddl.auto">update</property>
 
-
+        <mapping class="core.basesyntax.model.Comment" />
+        <mapping class="core.basesyntax.model.Message" />
+        <mapping class="core.basesyntax.model.MessageDetails" />
+        <mapping class="core.basesyntax.model.Smile" />
+        <mapping class="core.basesyntax.model.User" />
     </session-factory>
 </hibernate-configuration>