where does java specify locale information?

[wac]

For example. I think that in en_US locale, sorting is case insensitive. I wanted to verify that the locale is actually set up this way and the programmer didn't make a mistake. I thought there would be some system property file for each locale, but I haven't found one. I know that I can change the 'strength' of the sort, but I was wondering where the default values for each locale is specified.