I\'ve just started working on a project using the play framework,jongo and MongoDB. The project was initially written in Play 2.1 with pojos with an String id field annotat
The Jongo's behaviour has changed since 1.1 for a more consistent handling of its owns annotations.
If your '_id' is a String and you want this field to be stored into Mongo as a String then only @Id is needed.
@Id + @ObjectId on a String property means :
"My String property named 'foo' is a valid ObjectId. This property has to be stored with the name '_id' and have to be handled as an ObjectId."