Unable to fetch the data from the database when tables are mapped by many to many - spring-boot

Question

I am unable to fetch the users data from the database, and I also wonder how to handle the rest request in many to many cases for the same scenario.
I am using Spring Boot and Spring Data JPA. My code for the database is below:
CREATE TABLE `m3_group` (
`GROUP_ID` bigint(11) NOT NULL AUTO_INCREMENT,
`GROUP_NAME` varchar(30) DEFAULT NULL,
`GROUP_CREATED_DATE` datetime DEFAULT NULL,
`GROUP_ADMIN` varchar(14) DEFAULT NULL,
PRIMARY KEY (`GROUP_ID`)
)
ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
CREATE TABLE `m3_user` (
`USER_ID` bigint(11) NOT NULL AUTO_INCREMENT,
`USER_NAME` varchar(50) DEFAULT NULL,
PRIMARY KEY (`USER_ID`)
) ENGINE=InnoDB AUTO_INCREMENT=330 DEFAULT CHARSET=utf8;
CREATE TABLE `m3_user_group` (
`GROUP_USER_ID` bigint(11) DEFAULT NULL,
`GROUP_ID` bigint(11) DEFAULT NULL,
KEY `FK1_GROUP_ID` (`GROUP_ID`),
KEY `FK2_USER_ID` (`GROUP_USER_ID`),
CONSTRAINT `FK1_GROUP_ID` FOREIGN KEY (`GROUP_ID`) REFERENCES `m3_group` (`GROUP_ID`),
CONSTRAINT `FK2_USER_ID` FOREIGN KEY (`GROUP_USER_ID`) REFERENCES `m3_user` (`USER_ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
#Entity
#Table(name = "M3_USER")
public class User implements Serializable
{
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "USER_ID")
private long userId;
#NotBlank
#Column(name = "USER_NAME")
private String userName;
//many-to-many
#ManyToMany(mappedBy="listOfUsers",fetch=FetchType.EAGER)
private List<Group> listOfGroup=new ArrayList<Group>();
public long getUserId() {
return userId;
}
public void setUserId(long userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public List<Group> getListOfGroup() {
return listOfGroup;
}
public void setListOfGroup(List<Group> listOfGroup) {
this.listOfGroup = listOfGroup;
}
}
#Entity
#Table(name="M3_GROUP")
public class Group implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name="GROUP_ID")
private long groupId;
#Column(name="GROUP_NAME")
private String groupName;
#CreatedDate
#Temporal(TemporalType.TIMESTAMP)
#Column(name="GROUP_CREATED_DATE")
#JsonFormat(locale = "en-IN", shape = JsonFormat.Shape.STRING, pattern =
"yyyy-MM-dd HH:mm", timezone = "GMT+5:30")
private Date groupCreatedDate;
#Column(name="GROUP_ADMIN")
private String groupAdminMobileNumber;
//many-to-many
#ManyToMany(fetch=FetchType.EAGER)
#JoinTable(name = "M3_USER_GROUP", joinColumns = #JoinColumn(name =
"GROUP_USER_ID") , inverseJoinColumns = #JoinColumn(name = "GROUP_ID") )
private List<User> listOfUsers=new ArrayList<User>();
public long getGroupId() {
return groupId;
}
public void setGroupId(long groupId) {
this.groupId = groupId;
}
public String getGroupName() {
return groupName;
}
public void setGroupName(String groupName) {
this.groupName = groupName;
}
public Date getGroupCreatedDate() {
return groupCreatedDate;
}
public void setGroupCreatedDate(Date groupCreatedDate) {
this.groupCreatedDate = groupCreatedDate;
}
public String getGroupAdminMobileNumber() {
return groupAdminMobileNumber;
}
public void setGroupAdminMobileNumber(String groupAdminMobileNumber) {
this.groupAdminMobileNumber = groupAdminMobileNumber;
}
public List<User> getListOfUsers() {
return listOfUsers;
}
public void setListOfUsers(List<User> listOfUsers) {
this.listOfUsers = listOfUsers;
}
}
#Repository
public interface GroupRepository extends JpaRepository<Group, Long> {
List<Group> findByGroupId(long groupid);
}
#RestController
public class GroupController
{
#Autowired
GroupRepository groupRepository;
#RequestMapping(value="/find/{groupId}",method=RequestMethod.POST)
public ResponseEntity<List<Group>> find(#PathVariable String groupId)
{
long id=Long.parseLong(groupId);
List<Group> group = groupRepository.findByGroupId(id);
System.out.println(group.toString());
return new ResponseEntity<List<Group>>(group,HttpStatus.OK);
}
}
I have mapped the user and group table with many to many bidirectional and i am trying to fetch the data i.e users associated with the groupId but listOfUsers is showing empty.
My rest request is:
Http ://localhost:5000/find/1
And the response is:
[
{
"groupId": 1,
"groupName": "Om namo raghavendra",
"groupCreatedDate": "2017-05-17 12:48",
"groupAdminMobileNumber": "917676060664",
"listOfUsers":[
]
}
]
listOfUsers is empty, so I want to users by using groupId.