PL/SQL is a procedural language - mostly. But it can also be used to implement object-oriented features in Oracle Database. In "from the ground up" object-oriented languages like Java, everything is defined in classes. In Oracle Database, we have object types.
In this folder, you will find scripts that introduce you to the basics of object types, and more.
For more details and background, check out Steven Feuerstein's blog series that starts here: https://stevenfeuersteinonplsql.blogspot.com/2019/09/object-types-and-object-oriented.html