• Created a custom SessionFactory class that accepts DataSource and has a createSession method
• Created a custom Session class that accepts DataSource and has methods find(Class entityType, Object id) and close()
• Created custom annotations Table, Column
• Implemented method find using JDBC API
• Introduced session cache
• Store loaded entities to the map when it’s loaded
• Don’t call the DB if entity with given id is already loaded, return value from the map instead
• Introduced update mechanism
• Created another map that stores an entity snapshot copy (initial field values)
• On session close, compare entity with its copy and if at least one field has changed, perform UPDATE statement