BAEL-8210: Fixing Hibernate AnnotationException: Field is a @manytoone association and May Not Use @column (#18665)

Author: azhwani

persistence-modules/hibernate-exceptions-2/src/main/java/com/baeldung/hibernate/annotationexception/HibernateUtil.java

@@ -0,0 +1,39 @@
+package com.baeldung.hibernate.annotationexception;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.hibernate.SessionFactory;
+import org.hibernate.boot.Metadata;
+import org.hibernate.boot.MetadataSources;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.service.ServiceRegistry;
+
+public class HibernateUtil {
+    private static SessionFactory sessionFactory;
+
+    public static SessionFactory getSessionFactory() {
+        if (sessionFactory == null) {
+            Map<String, Object> settings = new HashMap<>();
+            settings.put("hibernate.connection.driver_class", "org.h2.Driver");
+            settings.put("hibernate.connection.url", "jdbc:h2:mem:test");
+            settings.put("hibernate.connection.username", "sa");
+            settings.put("hibernate.connection.password", "");
+            settings.put("hibernate.dialect", "org.hibernate.dialect.H2Dialect");
+            settings.put("hibernate.show_sql", "true");
+            settings.put("hibernate.hbm2ddl.auto", "update");
+
+            ServiceRegistry standardRegistry = new StandardServiceRegistryBuilder().applySettings(settings)
+                .build();
+
+            Metadata metadata = new MetadataSources(standardRegistry).addAnnotatedClasses(Student.class, University.class)
+                .getMetadataBuilder()
+                .build();
+
+            sessionFactory = metadata.getSessionFactoryBuilder()
+                .build();
+        }
+
+        return sessionFactory;
+    }
+}

persistence-modules/hibernate-exceptions-2/src/main/java/com/baeldung/hibernate/annotationexception/Student.java

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+package com.baeldung.hibernate.annotationexception;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+
+@Entity
+public class Student {
+    @Id
+    private int id;
+
+    @Column(name = "full_name")
+    private String fullName;
+
+    @ManyToOne
+    // switch these two lines to reproduce the exception
+    // @Column(name = "university")
+    @JoinColumn(name = "university_id")
+    private University university;
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getFullName() {
+        return fullName;
+    }
+
+    public void setFullName(String fullName) {
+        this.fullName = fullName;
+    }
+
+    public University getUniversity() {
+        return university;
+    }
+
+    public void setUniversity(University university) {
+        this.university = university;
+    }
+
+}

persistence-modules/hibernate-exceptions-2/src/main/java/com/baeldung/hibernate/annotationexception/University.java

@@ -0,0 +1,31 @@
+package com.baeldung.hibernate.annotationexception;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+
+@Entity
+public class University {
+    @Id
+    private int id;
+
+    @Column(name = "university_name")
+    private String name;
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+}

persistence-modules/hibernate-exceptions-2/src/test/java/com/baeldung/hibernate/annotationexception/ColumnNotAllowedOnManyToOneUnitTest.java

@@ -0,0 +1,35 @@
+package com.baeldung.hibernate.annotationexception;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.hibernate.Session;
+import org.hibernate.query.Query;
+import org.junit.jupiter.api.Test;
+
+class ColumnNotAllowedOnManyToOneUnitTest {
+
+    /*
+     * uncomment this test case to test the exception
+    @Test
+    void whenUsingColumnAnnotationWithManyToOneAnnotation_thenThrowAnnotationException() {
+        assertThatThrownBy(() -> {
+            HibernateUtil.getSessionFactory()
+                .openSession();
+        }).isInstanceOf(AnnotationException.class)
+            .hasMessageContaining("university' is a '@ManyToOne' association and may not use '@Column'");
+    }
+    */
+
+    @Test
+    void whenNotUsingColumnAnnotationWithManyToOneAnnotation_thenCorrect() {
+        Session session = HibernateUtil.getSessionFactory()
+            .openSession();
+
+        Query<Student> query = session.createQuery("FROM Student", Student.class);
+
+        assertThat(query.list()).isEmpty();
+
+        session.close();
+    }
+
+}