When Hibernate loads an object into a Session it creates a state snapshot of the current database state of the object, so that it can perform dirty checking against the snapshot.
As a read only object will never be modified, this snapshot is not needed and memory can be saved.
J. Li, P. Ren, Z. Chen, Z. Ren, and J. Ma. Proceedings of the 2017 ACM Conference on Information and Knowledge Management, page 1419--1428. New York, NY, USA, ACM Press, (2017)
B. Hidasi, A. Karatzoglou, L. Baltrunas, and D. Tikk. (2015)cite arxiv:1511.06939Comment: Camera ready version (17th February, 2016) Affiliation update (29th March, 2016).
J. Tang, and K. Wang. Proceedings of the Eleventh ACM International Conference on Web Search and Data Mining - WSDM \textquotesingle18, ACM Press, (2018)
J. Tang, and K. Wang. Proceedings of the Eleventh ACM International Conference on Web Search and Data Mining - WSDM \textquotesingle18, page 565--573. ACM Press, (2018)