Commonly use Utility methods in projects

Question

In many projects, we come across various utility methods, e.g.

• Email validation
• Convert from dd/mm/yyyy to mm/dd/yyyy or other date formats

I would like to know as what are the varoius common utility method that we genrally use?

I know that some methods are project specific but many will be common. I searched in net to get a list of as much as possible but none I found to be very informative.

Could you please help?

Well I am more interested in the method behaviour and not in their implementation.

If I can get the method names and what it does e.g. ConvertMMDDYYYY to ConvertDDMMYYYY it

will server my purpose.

Thanks