java.lang.NullPointerException
Caused by: java.lang.NullPointerException
    at com.nataniel.api.services.UserService.createUser(UserService.java:28)

import org.hibernate.annotations.Entity;
import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="USER")
public class User {
    @Id
    @GeneratedValue
    private Long id;

    @Column(name = "LOGIN")
    private String login;

    @Column(name = "NAME")
    private String name;

    @Column(name = "EMAIL")
    private String email;

    @Column(name = "PASSWORD")
    private String password;

    @Column(name = "CITY")
    private String city;

    @Column(name = "REGION")
    private String region;

    @Column(name = "BIRTHDATE")
    private String birthDate;

    public User() {
    }

    public User(String login, String name, String email, String password, String city, String region, String birthDate) {
        this.login = login;
        this.name = name;
        this.email = email;
        this.password = password;
        this.city = city;
        this.region = region;
        this.birthDate = birthDate;
    }

    // getters and setters
}

package com.nataniel.api.services;
import org.apache.camel.Exchange;
import org.json.JSONObject;
import org.springframework.stereotype.Service;
import com.nataniel.api.domain.User;
import org.springframework.transaction.annotation.Transactional;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.PersistenceContext;
@Service("userService")
public class UserService {

    @PersistenceContext
    transient EntityManager entityManager;

    @Transactional
    public String createUser(Exchange exchange) {
        JSONObject userAccountJSON = (JSONObject) exchange.getIn().getHeader("jsonRequest");

        User user = new User();
        user.setLogin(userAccountJSON.getString("login"));
        user.setEmail(userAccountJSON.getString("email"));
        user.setPassword(userAccountJSON.getString("password"));
        user.setName(userAccountJSON.getString("name"));
        user.setCity(userAccountJSON.getString("city"));
        user.setRegion(userAccountJSON.getString("region"));
        user.setBirthDate(userAccountJSON.getString("birthdate"));
        entityManager.persist(user);

        return userAccountJSON.toString();
    }
}