JPA EntityManager doesn't commit changes in SQLite database - sqlite

Question

I have an SQLite database. I work with it using EclipseLink and JPA. In addition I have an entity class User:
import com.vaadin.server.VaadinService;
import java.io.Serializable;
import javax.persistence.*;
#Entity
public class User implements Serializable {
#Id #GeneratedValue
long id; // Unique identifier of the user in the DB
String username; // Unique name used for login
String password; // Password used for login
public User() {
}
public User(String username, String password) {
this.username = username;
this.password = password;
}
public Long getId() {
return id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
In a registration form I create a user and then call an EntityManager to persist() the changes:
public int createUser(String username, String password, String password_confirmation) {
int regStatus = 0;
if(checkValidUsername(username)) {
if(checkValidPassword(password, password_confirmation)) {
EntityManager em = factory.createEntityManager();
try {
em.getTransaction().begin();
User user = new User(username, password);
em.persist(user);
em.getTransaction().commit();
}
catch(Exception e) {
System.out.println(e.getMessage());
regStatus = 3;
}
finally {
em.close();
}
}
else regStatus = 2; // Password mismatch
}
else regStatus = 1; // User with selected username already present in DB
return regStatus;
}
It works without any problems. I get each and every newly registered user in my USER table. However when I try to change the password it doesn't work. Here are the methods that are related to this procedure:
// Inside the controller for my settings view - here the user can change various things related to his/her profile
public void setCurrentUser() {
currentUser = UserController.findUserByName((String)VaadinSession.getCurrent().getAttribute("username")); // findUserByName() is a static method
}
// Inside the User controller I have multiple methods for common user-related queries; here I use the username that I have retrieved from the VaadinSession's attribute "username" to execute a query and get the User entity (I make sure that a user's name is unique so getting a single result here is not a problem)
public static User findUserByName(String username) {
if(username == null) return null;
factory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
EntityManager em = factory.createEntityManager();
User user = null;
try{
Query q = em.createQuery("SELECT u FROM User u WHERE u.username = :username");
q.setParameter("username", username);
user = (User)q.getSingleResult();
}
catch(Exception e){
System.err.println(e.getMessage());
}
finally {
em.close();
}
return user;
}
// Inside the controller fpr my settings view (where I change the password)
public int changePassword(String currentPassword, String newPassword, String newPasswordConfirmation) {
if(newPassword.isEmpty()) return 1;
if(!newPassword.equals(newPasswordConfirmation)) return 2; // Incorrect confirmation
if(!currentPassword.equals(currentUser.getPassword())) return 3; // Given current password doesn't match the one stored in the database for this user
int resStatus = 0;
EntityManager em = factory.createEntityManager();
try {
em.getTransaction().begin();
currentUser.setPassword(newPassword);
em.getTransaction().commit(); // NO ERRORS at all...
}
catch(Exception e) {
System.out.println(e.getMessage());
resStatus = 4; // Exception
}
finally {
em.close();
}
return resStatus;
}
I have also tried using EntityManager.find(...), which should return the same row from the USER table (and it does) but the result is again the same - transaction begins, finishes, entity manager closes but the table USER for the supposedly changed user is the same.
Any ideas? I have used the same routine in another project but for setting other things. The database there was PostreSQL and I haven't encountered such issues. Here with the SQLite database I get no errors but the commit fails somehow.

Answer 1

I just develop with hibernate etc. but it will be the same, because both implements JPA.
If you start a transaction JPA will remember all entities you load in this transaction and if you change something you will see the changes in db (after commit).
But in your transaction JPA don't recognize your entity and so the changes will not persists. Try to load the entity in the transaction. Like...
em.getTransaction().begin();
em.find(User.class, currentUser.getId()); //Reload the User from db, so it is attached to the session
currentUser.setPassword(newPassword);
em.getTransaction().commit();
More Information about the methods:
https://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html#refresh(java.lang.Object)
https://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html#merge(T)
http://www.objectdb.com/java/jpa/persistence/managed