java - Validation doesn't work on EntityManager.merge() -

i have few validations on entity, @notnull, , generation,

@id @generatedvalue(strategy = auto) @column(name = "id") private long id;  @column @generatedvalue(strategy = generationtype.auto) private long referencenumber; 

however when calling entitymanager.merge() values not generated. null fields @notnull annotation passed without complain. id not generated.

should switch generation on somehow? how, , where?

in addition kraftan's answer:

• by default automatic bean validation in jpa 2.0 works if validation provider "present in environment", otherwise silently doesn't work. can add

  <validation-mode>callback</validation-mode> 

  to persistence.xml in order generate error if validation provider not found.

• jpa doesn't support generation of arbitrary (non-id) properties. jpa providers may have extensions.