Perist not throwing exception

Question

Hi everyone,
I am new to JPA, and currently trying to persist/update an entity to a HSQL database. According to the API, the persist method of the class EntityManager, throws an exception if we try to persist an entity which already exists, but in my case, it seems to update the entity, if it exists.
Here's a snippet of the commit code
public void commit(Object obj){
        if(entityManager == null) {
            entityManager = getEmf().createEntityManager();
        if(entityTransaction == null){
            entityTransaction = entityManager.getTransaction();
        if(!entityTransaction.isActive()){
            entityTransaction.begin();
        entityManager.persist(obj);
        try{
            entityTransaction.commit();
        } finally {
            close();
private void close(){
        EntityManager tempEntityManager = entityManager;
        EntityTransaction tempEntityTransaction = entityTransaction;
        entityManager = null;
        entityTransaction = null;
        try{
            if(tempEntityTransaction != null &&  tempEntityTransaction.isActive()){
                tempEntityTransaction.rollback();
        } finally{
            if(tempEntityManager != null) {
                tempEntityManager.close();
    }As you can see, my commit method calls the persist method always, so if I try to commit an entity twice, it should throw an exception, but instead it updates the entity. Could any of you tell me why this is the case?

Answer 1

Look at the setLenient method.
Also, read the part in the docs about when the number of characters does and does not matter when parsing.