Naming convention for properties in property file

Question

What are the naming conventions for property names defined in properties files in Java? Can I use uppercase or only lowercase?

For example: bankAccountNumber or bank.acc

Answer 1

In JSF you can see in ValidationMessages.properties something

javax.validation.constraints.Pattern.message

or in JsfMessages.properties

javax.faces.component.UISelectOne.INVALID

So you can use wherever you like, i like just lowercase, package formatted