Hibernate relationship code - spring

Question

Getting following error while executing the Hibernate program for a relationship:
Exception in thread "main" org.hibernate.MappingException: Could not determine type for: com.Employee.Department.Department, at table: Employee, for columns: [org.hibernate.mapping.Column(dept)]
The code is shown in below:
Employee.java: Contains the 1-M relationship
package com.Employee.Employee;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import com.Employee.Department.Department;
#Entity
#Table(name = "Employee_1toMany")
public class Employee {
#Id
#GeneratedValue
#Column(name = "EId")
private int emp_id;
#Column(name = "EName")
private String name;
private Department dept;
public int getEmp_id() {
return emp_id;
}
public void setEmp_id(int emp_id) {
this.emp_id = emp_id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
#ManyToOne
#JoinColumn(name = "DepartmentID")
public Department getDept() {
return dept;
}
public void setDept(Department dept) {
this.dept = dept;
}
}
Department.java: Contains M to 1 relationship
package com.Employee.Department;
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import com.Employee.Employee.Employee;
#Entity
#Table(name = "Department_1toMany")
public class Department {
#Id
#GeneratedValue
#Column(name = "DId")
private int Dept_id;
#Column(name = "DName")
private String Dept_name;
private List<Employee> emp;
public int getDept_id() {
return Dept_id;
}
public void setDept_id(int dept_id) {
Dept_id = dept_id;
}
public String getDept_name() {
return Dept_name;
}
public void setDept_name(String dept_name) {
Dept_name = dept_name;
}
#OneToMany(targetEntity = Employee.class, mappedBy = "dept", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
public List<Employee> getEmp() {
return emp;
}
public void setEmp(List<Employee> emp) {
this.emp = emp;
}
}
MainClass.java:
package com.Employee.MainClass;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import com.Employee.Department.Department;
import com.Employee.Employee.Employee;
public class MainApp {
public static void main(String[] args) {
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Department dept = new Department();
dept.setDept_name("Modern College");
Employee emp1 = new Employee();
emp1.setName("Rakesh");
Employee emp2 = new Employee();
emp2.setName("Sagar");
emp1.setDept(dept);
emp2.setDept(dept);
session.save(dept);
session.save(emp1);
session.save(emp2);
tx.commit();
}
}
hibernate.cfg.xml: This is the configuration class
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost/EMP_PRACTISE</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
<property name="hibernate.hbm2ddl.auto">create</property>
<property name="hibernate.show_sql">true</property>
<mapping class="com.Employee.Department.Department"></mapping>
<mapping class="com.Employee.Employee.Employee"></mapping>
</session-factory>
</hibernate-configuration>
Exception in detail:
Exception in thread "main" org.hibernate.MappingException: Could not determine type for: com.Employee.Department.Department, at table: Employee, for columns: [org.hibernate.mapping.Column(dept)]
at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:455)
at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:422)
at org.hibernate.mapping.Property.isValid(Property.java:226)
at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:597)
at org.hibernate.mapping.RootClass.validate(RootClass.java:265)
at org.hibernate.boot.internal.MetadataImpl.validate(MetadataImpl.java:329)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:451)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:710)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)
at com.Employee.MainClass.MainApp.main(MainApp.java:13)

Answer 1

I believe you cannot mix fields and getter methods annotations. Place them to corresponding fields.
Employee.java
#ManyToOne
#JoinColumn(name = "DepartmentID")
private Department dept;
// mapping annotation on the field
public Department getDept() {
return dept;
}
Department.java
#OneToMany(targetEntity = Employee.class, mappedBy = "dept", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private List<Employee> emp;
// mapping annotation on the field
public List<Employee> getEmp() {
return emp;
}