Java JCE providers - what does "clean room implementation" mean?

Question

I'm required to write a JCE provider. I have learned that I need to use the bouncy castle clean room implementation. Could you please tell me what "clean room implementation" means in in this context?

Answer 1

Clean room implementation means in this context that the code was written only from the description and specification, but not with access to any potentially troublesome code.

This is important as the Sun source code previously was under a license which was incompatible with especially GPL distributions. By ensuring that the code was not written without any access to such code, it is guaranteed that the Sun license could not later be found to apply to the clean room implementation, and then again be incompatible with the GPL license or any other restrictions.

In other words, it is a guarantee that the license shown will hold.