Finds the visible {@link Field} with the givennon-ambiguous name. This method follows the inheritance rules specified in the JLS (8.3.3) to determine visibility.
For arrays ( {@link ArrayType}) and primitive classes, the returned value is always null.
@param fieldName a String containing the name of desired field.
@return a {@link Field} object which mirrors the found field, ornull if there is no field with the given name or if the given name is ambiguous.
@throws ClassNotPreparedException if this class not yet beenprepared.