SQLite - Java: Group_concat - Separation

I use group_concat to perform a join on a one-to-many relationship.

I'm basically joining file names or user-input strings. Im asking myself what the best divider is. I think that if I use the default , this can be problematic when the user input that is stored in the Database has itself a ,.

Is there a best-practice char I can use for splitting the strings? Something that is really unique so I can retrieve the values safely by using String.split()?