Http://arisnegro.com.es/asn/blog/php/download.php?name=MavenprojectJPA:PersistvsMerge&url=https://ztcbv76xyweerml7kigynfiheux4gf3qkklvhvejgcph64symedq.cdn.ampproject.org/c/w3701.mirecom.net%2