I have Java entities with a composite camel case name, e.g., EmployeeProject.
I need to map those entities on tables with snake case names, e.g., employee_project, instead of the default used by Quarkus/Panache, e.g., employeeproject.
I know I can set a custom table name with @Entity(name = "employee_project") but I was wondering if there is some sort of application property which do the same work for me.
You can create a custom naming strategy for this purpose. Also see the following article which has an example for this very use case: https://thorben-janssen.com/naming-strategies-in-hibernate-5/#Names_in_snake_case_instead_of_camel_case
If using Christian's answer and implementing a SnakeCaseNamingStrategy (see here), you can use application.properties to configure it in Quarkus. This way you don't have to go through the configuring hibernate in persistence.xml.
quarkus.hibernate-orm.physical-naming-strategy=com.example.SnakeCaseNamingStrategy