How would one go about proving to management that a batch reformat of all .java files in a large code base (to place the code in compliance with the company's coding standards) is safe and will not affect functionality.

The answers would have to appease the non-technical and the technical alike.

**Edit: 2010-03-12**Clarification for the technical among you; reformat = white space-only changes - no "organizing imports" or "reordering of member variables, methods, etc."

**Edit: 2010-03-12** Thank you for the numerous responses. I am a surprised that so many of the readers have voted up mrjoltcola's response since it is simply a statement about about being paranoid and in no way proposes an answer to my question. Moreover, there is even a comment by the same contributor reiterating the question. WizzardOfOdds seconded this viewpoint (but you may not have read all the comments to see it). -jtsampson

**Edit: 2010-03-12** I will post my own answer soon, though John Skeet's answer was right on the money with the MD5 suggestion (note -g:none to turn debugging off). Though it only covered the technical aspects. -jtsampson

**2010-03-15** I added my own answer below. In response to what does "safe" mean, I meant that the functionality of the Java code would not be affected. A simple study of the Java compiler shows this to be the case (with a few caveats). Thos caveats were "white space only" and were pointed out by several posters. However this is not something you want to try to explain to BizOps. My aim was to elicit "how to justify doing this" type of answers and I got several great responses.

Several people mentioned source control and the "fun" that goes along with it. I specifically did not mention that as that situation is already well understood (within my context). Beware of the "gas station" effect. See my answer below.