diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..c5f3f6b
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,3 @@
+{
+    "java.configuration.updateBuildConfiguration": "interactive"
+}
\ No newline at end of file
diff --git a/back_end/pom.xml b/back_end/pom.xml
index 54df3f5..e8bf001 100644
--- a/back_end/pom.xml
+++ b/back_end/pom.xml
@@ -28,7 +28,7 @@
 		<url/>
 	</scm>
 	<properties>
-		<java.version>25</java.version>
+		<java.version>17</java.version>
 	</properties>
 	<dependencies>
 		<dependency>
@@ -97,7 +97,13 @@
 			<artifactId>spring-boot-starter-thymeleaf-test</artifactId>
 			<scope>test</scope>
 		</dependency>
-	</dependencies>
+		<dependency>
+			<groupId>org.projectlombok</groupId>
+			<artifactId>lombok</artifactId>
+			<version>1.18.32</version>
+			<scope>provided</scope>
+		</dependency>
+			</dependencies>
 
 	<build>
 		<plugins>
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/Activite.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/Activite.java
new file mode 100644
index 0000000..8b7343c
--- /dev/null
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/Activite.java
@@ -0,0 +1,53 @@
+package hackathon.FrisbYEE.jpa;
+
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToOne;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+import jakarta.persistence.Access;
+import jakarta.persistence.AccessType;
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.ElementCollection;
+import jakarta.persistence.Entity;
+
+@Entity
+@Getter @Setter @NoArgsConstructor
+@Access(AccessType.FIELD)
+
+public class Activite implements Serializable {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+    private String name;
+    private String theme;
+    private Long duree;
+    @ElementCollection
+    private List<String> dataActivite = new ArrayList<>();    
+
+    @ManyToOne(cascade = CascadeType.PERSIST)
+    private Session session;
+
+    public Activite(String name) {
+        this.name = name;
+    }
+
+    public Activite(String name, String theme, List<String> dataActivite, Long duree) {
+        this.name = name;
+        this.theme = theme;
+        this.duree = duree;
+        this.dataActivite = dataActivite;
+    }
+
+    @Override
+    public String toString() {
+        return "Activite [id=" + id + " , name=" + name + "]";
+    }
+
+}
\ No newline at end of file
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/Athlete.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/Athlete.java
new file mode 100644
index 0000000..73e4ece
--- /dev/null
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/Athlete.java
@@ -0,0 +1,28 @@
+package hackathon.FrisbYEE.jpa;
+
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToMany;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+import java.time.LocalDateTime;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+import jakarta.persistence.Access;
+import jakarta.persistence.AccessType;
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.ElementCollection;
+import jakarta.persistence.Entity;
+
+@Entity
+@Getter @Setter @NoArgsConstructor
+@Access(AccessType.FIELD)
+public class Athlete {
+    
+    
+}
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/Coach.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/Coach.java
new file mode 100644
index 0000000..99287fc
--- /dev/null
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/Coach.java
@@ -0,0 +1,28 @@
+package hackathon.FrisbYEE.jpa;
+
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToMany;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+import java.time.LocalDateTime;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+import jakarta.persistence.Access;
+import jakarta.persistence.AccessType;
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.ElementCollection;
+import jakarta.persistence.Entity;
+
+@Entity
+@Getter @Setter @NoArgsConstructor
+@Access(AccessType.FIELD)
+public class Coach {
+    
+    
+}
diff --git a/back_end/src/main/java/hackathon/FrisbYEE/jpa/Session.java b/back_end/src/main/java/hackathon/FrisbYEE/jpa/Session.java
new file mode 100644
index 0000000..d77c880
--- /dev/null
+++ b/back_end/src/main/java/hackathon/FrisbYEE/jpa/Session.java
@@ -0,0 +1,59 @@
+package hackathon.FrisbYEE.jpa;
+
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToMany;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+import jakarta.persistence.Access;
+import jakarta.persistence.AccessType;
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+
+@Entity
+@Getter @Setter @NoArgsConstructor
+@Access(AccessType.FIELD)
+
+public class Session {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+    private String name;
+    private Boolean isRecurrent;
+    private LocalDateTime creneau;
+    private Long duree;
+    private String groupe;
+
+    @ManyToOne(cascade = CascadeType.PERSIST)
+    private Coach coach; // un coach par session
+
+    @ManyToMany(cascade = CascadeType.PERSIST)
+    private List<Athlete> athletes = new ArrayList<>(); // plusieurs athlètes par session
+
+    @OneToMany(mappedBy = "session", cascade = CascadeType.PERSIST)
+    private List<Activite> activites = new ArrayList<>(); // plusieurs activités par session
+
+    public Session(String name) {
+        this.name = name;
+    }
+
+    public Session(String name, Boolean isRecurrent, LocalDateTime creneau, Long duree, String groupe) {
+        this.name = name;
+        this.isRecurrent = isRecurrent;
+        this.creneau = creneau;
+        this.duree = duree;
+        this.groupe = groupe;
+    }
+
+    @Override
+    public String toString() {
+        return "Session [id=" + id + " , name=" + name + "]";
+    }
+}
\ No newline at end of file