This is a copy of the EmailValidator and dependencies from the Apache commons-validator library. It's based on trunk as of 4/15/11 (1.4, r1087179 | 2011-03-30).
The reason for the inclusion here is because the EmailValidator in commons-validator-1.3.1 depends on the Apache ORO library. The ORO library uses recursion for one of it's reg-ex matching routines, which leads to a StackOverflowException when running on Android with a very large email address. The new 1.4 release uses the standard Java RegEx classes, and does not suffer from this bug. When Apache releases commons-validator-1.4 we should switch to it, and remove these copies.