Paper was created in Sweden in 2015. The main contributor is Oleksii Masnyi (Aleksey Masny), an android software developer. It was initially developed to be used in AppDialer, a smart phone application for searching other apps. The system was mainly developed between 2015 and 2017. The first version was released with main object-oriented structure, and newer versions were later released with major updates in methods, data format and custom APIs.
Paper uses concurrent hash map and semaphore to deal with multi-thread reading and writing for single operation, but no concurrency control protocol is being used to protect transactions.
Paper uses custom strings as keys, and objects as values, which is a combination of key/value data model and object-oriented data model.
Paper uses Java concurrent hash maps to store objects.
N-ary Storage Model (Row/Record)
Paper maintains backup files when performing writing. When writing is done successfully, backup file is deleted.
Paper is a database system designed for Android.