Can't save many-to-many relations by form in JSP - spring

Question

The Context
I have a simple workshop application with three entities - Job, Employee and Customer. I am trying to create web interface which will add new Job in this case. Job has many to many relations with Employee and Customer. In Job entity there are lists of Employee and Customer as well.
The Problem
When I try to post my request with new Job through HTTP I get Bad Request 400 with description:
The server cannot or will not process the request due to something
that is perceived to be a client error (e.g., malformed request
syntax, invalid request message framing, or deceptive request
routing).
I don't know where excactly is bug.
Forms for adding Customer and Employee work fine.
The Code
Entities:
Employee
#Component
#Entity
public class Employee {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Pattern (regexp="[a-zA-Z]+")
#NotEmpty
private String employeeName;
#Pattern (regexp="[a-zA-Z]+")
#NotEmpty
private String employeeSurname;
#ManyToMany(mappedBy = "employeeList")
private List<Job> jobList;
public Employee() {
}
public Employee(int id, String employeeName, String employeeSurname) {
this.id = id;
this.employeeName = employeeName;
this.employeeSurname = employeeSurname;
}
public Employee(String employeeName, String employeeSurname) {
this.employeeName = employeeName;
this.employeeSurname = employeeSurname;
}
public List<Job> getJobList() {
return jobList;
}
public void setJobList(List<Job> jobList) {
this.jobList = jobList;
}
public String getEmployeeName() {
return employeeName;
}
public void setEmployeeName(String employeeName) {
this.employeeName = employeeName;
}
public String getEmployeeSurname() {
return employeeSurname;
}
public void setEmployeeSurname(String employeeSurname) {
this.employeeSurname = employeeSurname;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}}
Customer
#Component
#Entity
public class Customer {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Pattern(regexp="[a-zA-Z]+")
#NotEmpty
private String CustomerName;
#Pattern (regexp="[a-zA-Z]+")
#NotEmpty
private String CustomerSurname;
#Pattern (regexp = "\\w+")
#NotEmpty
private String car;
private int phonenumber;
#ManyToMany(mappedBy = "customerList")
private List<Job> jobList;
public Customer(String customerName, String customerSurname, String car, int phonenumber) {
CustomerName = customerName;
CustomerSurname = customerSurname;
this.car = car;
this.phonenumber = phonenumber;
}
public Customer(int id, String customerName, String customerSurname, String car, int phonenumber) {
this.id=id;
CustomerName = customerName;
CustomerSurname = customerSurname;
this.car = car;
this.phonenumber = phonenumber;
}
public Customer() {
}
public List<Job> getJobList() {
return jobList;
}
public void setJobList(List<Job> jobList) {
this.jobList = jobList;
}
public String getCustomerName() {
return CustomerName;
}
public void setCustomerName(String customerName) {
CustomerName = customerName;
}
public String getCustomerSurname() {
return CustomerSurname;
}
public void setCustomerSurname(String customerSurname) {
CustomerSurname = customerSurname;
}
public int getPhonenumber() {
return phonenumber;
}
public void setPhonenumber(int phonenumber) {
this.phonenumber = phonenumber;
}
public String getCar() {
return car;
}
public void setCar(String car) {
this.car = car;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}}
Job
#Component
#Entity
public class Job {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#NotEmpty
#Pattern(regexp="[a-zA-Z]+")
private String jobName;
#ManyToMany(fetch = FetchType.EAGER)
private List<Employee> employeeList;
#LazyCollection(LazyCollectionOption.FALSE)
#ManyToMany
private List<Customer> customerList;
public Job() {
}
public Job(String jobName, List<Employee> employeeList, List<Customer> customerList) {
this.jobName = jobName;
this.employeeList = employeeList;
this.customerList = customerList;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getJobName() {
return jobName;
}
public void setJobName(String jobName) {
this.jobName = jobName;
}
public List<Employee> getEmployeeList() {
return employeeList;
}
public void setEmployeeList(List<Employee> employeeList) {
this.employeeList = employeeList;
}
public List<Customer> getCustomerList() {
return customerList;
}
public void setCustomerList(List<Customer> customerList) {
this.customerList = customerList;
}}
DaoImpl
JobDaoImpl
#Repository
public class JobDaoImpl implements JobDao {
#PersistenceContext
EntityManager entityManager;
#Override
public List<Job> findAllJobs() {
return entityManager.createQuery("select j from Job j order by j.id", Job.class)
.getResultList();
}
#Override
public Job addJob(Job job) {
entityManager.persist(job);
entityManager.flush();
entityManager.refresh(job);
return job;
}}
Service
JobService
#Service
#Transactional
public class JobService {
private JobDao jobDao;
public List<Job> findAllJobs(){
return jobDao.findAllJobs();
}
public Job addNewJob(Job job){return jobDao.addJob(job);}
public JobService(JobDao jobDao) {
this.jobDao = jobDao;
}
}
Controller
JobController
#Controller
public class JobController {
JobService jobService;
EmployeeService employeeService;
CustomerService customerService;
public JobController(JobService jobService, EmployeeService employeeService, CustomerService customerService) {
this.jobService = jobService;
this.employeeService = employeeService;
this.customerService = customerService;
}
//JOB INDEX
#RequestMapping("job-index.html")
public ModelAndView getJobIndex() {
ModelAndView modelAndView = new ModelAndView("jobViews/jobIndex");
return modelAndView;
}
//SHOW EMPLOYEES
#RequestMapping("show-jobs.html")
public ModelAndView getAllJobs() {
ModelAndView modelAndView = new ModelAndView("jobViews/jobs");
modelAndView.addObject("jobs", jobService.findAllJobs());
return modelAndView;
}
//ADD NEW JOB GET METHOD
#GetMapping(value = "add-job.html")
public ModelAndView addNewJob(){
return new ModelAndView("jobViews/addJob","job", new Job());
}
//ADD NEW JOB POST METHOD
#PostMapping(value = "add-job.html")
public ModelAndView addNewJob(#ModelAttribute Job job){
return new ModelAndView("jobViews/addJobConfirmation","job",job);
}
#ModelAttribute("employeeInit")
public List<Employee> initializeEmployees() {
return employeeService.findAllEmployee();
}
#ModelAttribute("customerInit")
public List<Customer> initializeCustomer(){ return customerService.findAllCustomer();}}
JSP Views
addJob.jsp
<f:form method="post" modelAttribute="job">
<p>Job name:<f:input path="jobName"/></p>
<f:hidden path="id"/>
<f:select path="employeeList" multiple="true">
<f:options items="${employeeInit}" itemLabel="employeeSurname" itemValue="id"></f:options>
</f:select>
<f:select path="customerList" multiple="true">
<f:options items="${customerInit}" itemLabel="customerSurname" itemValue="id"></f:options>
</f:select>
<button type="submit">Add</button>