@Entity
@Table(name = "user", schema = "rps_am")
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class,property = "id", scope = UserEntity.class)

public class UserEntity {
    @ApiModelProperty(required = true, hidden = true)
    private Long id;
    private String logonId;
    private String emailAddress;
    private String password;
    private Collection<UserRoleEntity> userRolesById;
    @Id
    @Column(name = "ID")
    @GeneratedValue(strategy = GenerationType.AUTO)
    public Long getId() {
        return id;
}
public void setId(Long id) {
   this.id = id;
    }
    @Basic
    @Column(name = "PASSWORD")
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }

    @Basic
    @Column(name = "EMAIL_ADDRESS")
    public String getEmailAddress() {
        return this.emailAddress;
    }
    public void setEmailAddress(String emailAddress) {
        this.emailAddress = emailAddress;
    }
    @Basic
    @Column(name = "LOGON_ID")
    public String getLogonId() {
        return logonId;
    }
    public void setLogonId(String logonId) {
        this.logonId = logonId;
    }
    @OneToMany(mappedBy = "userByUserId", fetch=FetchType.EAGER) //If I make it LAZY my problem is sloved.
    @Fetch(FetchMode.JOIN)
    @Transactional
    @JsonIgnore
    public Collection<UserRoleEntity> getUserRolesById() {
        return userRolesById;
    }
    public void setUserRolesById(Collection<UserRoleEntity> userRolesById) {
        this.userRolesById = userRolesById;
    }
    private List<RoleEntity> roles;
    @Transient
    public List<RoleEntity> getRoles() {
        if (roles == null) {
            Collection<UserRoleEntity> c = getUserRolesById();
            roles = new ArrayList<>();
            for (UserRoleEntity userRoleEntity : c) {
                roles.add(userRoleEntity.getRoleByRoleId());
            }
        }
        return roles;
    }
    public void setRoles(List<RoleEntity> roles) {
        this.roles = roles;
    }
}



@Entity
@Table(name = "role", schema = "rps_am")
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class,property = "id", scope = RoleEntity.class)
public class RoleEntity {
    @ApiModelProperty(required = true, hidden = true)
    private Long id;
    private String roleName;
    private Collection<UserRoleEntity> userRolesById;

    @Id
    @Column(name = "ID")
    @GeneratedValue(strategy = GenerationType.AUTO)
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    @Basic
    @Column(name = "ROLE_NAME")
    public String getRoleName() {
        return roleName;
    }

    public void setRoleName(String roleName) {
        this.roleName = roleName;
    }

    @JsonIgnore
    @OneToMany(mappedBy = "roleByRoleId")
    public Collection<UserRoleEntity> getUserRolesById() {
        return userRolesById;
    }

    public void setUserRolesById(Collection<UserRoleEntity> userRolesById) {
        this.userRolesById = userRolesById;
    }
}

@RequestMapping(value = "userrole", method = RequestMethod.POST)
    public UserRoleEntity create(@RequestBody UserRoleEntity obj) {

        UserEntity usr = userRepository.findById(obj.getUserId());
        RoleEntity role = roleRepository.findById(obj.getRoleId());
        obj.setRoleByRoleId(role); // I added one role for specific user e.g HR (assume user already has role ADMIN)
        obj.setUserByUserId(usr);
        UserRoleEntity rc =  userRoleRepository.saveAndFlush(obj); // now after this line user has role ADMIN and HR
        UserEntity user = userRepository.findByLogonId(obj.getLoginId);
        Collection<UserRoleEntity> urs = user.getUserRolesById();// after execution of this line i am getting only ADMIN as a role I am not able to get HR
...
...
        return rc;
    }