java - Why extra query executed while fetching data in Many to One relationship? -

i have 2 entities student , college. single college has multiple student.

@entity public class college {      @id     @generatedvalue     private int collegeid;      private string collegename;      public int getcollegeid() {         return collegeid;     }      public void setcollegeid(int collegeid) {         this.collegeid = collegeid;     }      public string getcollegename() {         return collegename;     }      public void setcollegename(string collegename) {         this.collegename = collegename;     } }   @entity public class student {      @id     @generatedvalue     private int studentid;      private string studentname;      @manytoone(cascade = cascadetype.all)     private college college;      public int getstudentid() {         return studentid;     }      public void setstudentid(int studentid) {         this.studentid = studentid;     }      public string getstudentname() {         return studentname;     }      public void setstudentname(string studentname) {         this.studentname = studentname;     }      public college getcollege() {         return college;     }      public void setcollege(college college) {         this.college = college;     } } 

i want fetch students of particular college.

as can see in below code hql query have written : "select student "+student.class.getname()+" student student.college.collegeid = 1"

on execution of following code 2 sql queries fired follows:

hibernate: select student0_.studentid studentid1_1_, student0_.college_collegeid college_collegeid3_1_, student0_.studentname studentname2_1_ mevada.student student0_ student0_.college_collegeid=1 hibernate: select college0_.collegeid collegeid1_0_0_, college0_.collegename collegename2_0_0_ mevada.college college0_ college0_.collegeid=? 

ideally first query sufficient fetch required students , working when fire directly database.

why second query executed? how can stop hibernate executing query? utility class:

public class manytoone {      public static void main(string[] args) {         entitymanagerfactory emf = persistence.createentitymanagerfactory("org.hibernate.examples");          entitymanager em = emf.createentitymanager();          college college1 = new college();         college1.setcollegename("college1");           college college2 = new college();         college2.setcollegename("college2");          student student1 = new student();         student1.setstudentname("std1");         student1.setcollege(college1);           student student2 = new student();         student2.setstudentname("std2");         student2.setcollege(college2);          student student3 = new student();         student3.setstudentname("std3");         student3.setcollege(college1);          student student4 = new student();         student4.setstudentname("std4");         student4.setcollege(college1);          em.gettransaction().begin();          em.persist(college1);         em.persist(college2);         em.persist(student1);         em.persist(student2);         em.persist(student3);         em.persist(student4);          em.gettransaction().commit();         em.close();          em = emf.createentitymanager();         em.gettransaction().begin();          string querystring = "select student "+student.class.getname()+" student student.college.collegeid = 1";          query query = em.createquery(querystring);          list<student> students = query.getresultlist();          em.gettransaction().commit();         em.close();         emf.close();      } } 

it's because of this

@manytoone(cascade = cascadetype.all) private college college; 

@manytoone eager default, means populated when student fetched database. set relation lazy, delay second query until call student.getcollege(). if know you'll need college data well, should able in 1 query this

"select student " + student.class.getname() + " student inner join student.college col col.collegeid = 1"