avoided dynamically creating class methods. Apparently, in JRuby at least, there is a lock on that.

[patcheng]

I was testing with JDNI (Commons DBCP) with unlimited database connection. Might not be as bad if using DataMapper's connection pool.

[dkubb]

@dbussink what do you think about this change? It looks great to me, and it removes the redefinition of the method.