Q: is it good or bad practice to design your code to treat differently situations when a collection is empty vs. when a collection is null?

Part of the project I'm working on got updated, and at some point somebody started sending empty collections instead of null as parameters to a method.

This led to a single bug first, which then led me to change if (null == myCollection) with if (CollectionUtils.isEmpty(myCollection)), which in the end led to a cascade of several bugs. This way I discovered that a lot of the code was treating differently these two situations:

• when a collection is empty (ie. the user specifically wanted to have nothing here)
• when a collection is null (ie. the user did not mention anything here)

Hence, my question: is this good or bad design practice ?

Thank you.