PrivateAccessor
http://junit-addons.sourceforge.net/junitx/util/PrivateAccessor.html
こいつがあれば
Class clazz = Hoge.getClass(); Fiels field = c.getDeclaredFiled("foo"); field.setAccessible(true); (String)field.get(clazz);
が
(String)PrivateAccessor.getField(hoge, "foo");
に変身