JPA-Hibernate Lazy Fetching -

i trying understand behaviour of jpa-hibernate in below situation.

i have 2 entities, department , employee have 1 many relationship. trying implement using jpa-hibernate.

here department entity:

@entity @table(name="department") public class department {      @id        @generatedvalue        @column(name="department_id")     private long departmentid;      @column(name="dept_name")     private string departmentname;      @onetomany(mappedby="department")     private set<employee> employees; } 

here employee entity:

@entity @table(name="employee") public class employee {      @id     @generatedvalue     @column(name="employee_id")     private long employeeid;      @column(name="firstname")     private string firstname;      @column(name="lastname")     private string lastname;      @manytoone(fetch = fetchtype.lazy)     @joincolumn(name="department_id")     private department department;      public employee() {      }      public employee(string firstname, string lastname, string phone) {         this.firstname = firstname;         this.lastname = lastname;         this.birthdate = new date(system.currenttimemillis());         this.cellphone = phone;     }  } 

while fetching employee dont want fetch department. use fetchtype.lazy. suppose few employees associated 2 departments , in such case when fetch employee, exception department has multiple records. since use fetchtype.lazy, assumption department should not fetched , hence no matter if employee associated 1 department or 2 department, should able fetch employee.

can me understand why exception?

thanks.