Spring JpaRepositroy.save() does not appear to throw exception on duplicate saves

Question

I\'m currently playing around on Spring boot 1.4.2 in which I\'ve pulled in Spring-boot-starter-web and Spring-boot-starter-jpa.

My main issue is that when I save a

Answer 1

To build upon Shazins answer and to clarify. the CrudRepositroy.save() or JpaRespository.saveAndFlush() both delegate to the following method

SimpleJpaRepository.java

@Transactional
public  S save(S entity) {

    if (entityInformation.isNew(entity)) {
        em.persist(entity);
        return entity;
    } else {
        return em.merge(entity);
    }
}

Hence if a user tries to create a new entity that so happens to have the same id as an existing entity Spring data will just update that entity.

To achieve what I originally wanted the only thing I could find was to drop back down to JPA solely, that is

@Transactional
@PostMapping("/createProduct")
public Product createProduct(@RequestBody @Valid Product product) {
    try {
        entityManager.persist(product);
        entityManager.flush();
    }catch (RuntimeException ex) {
        System.err.println(ex.getCause().getMessage());
    }

    return product;
}

Here if we try to persist and new entity with an id already existing in the database it will throw will throw the constraint violation exception as we originally wanted.