private final int
getCred(int section, boolean isAuth) {
	if (section == Section.ANSWER) {
		if (isAuth)
			return Credibility.AUTH_ANSWER;
		else
			return Credibility.NONAUTH_ANSWER;
	} else if (section == Section.AUTHORITY) {
		if (isAuth)
			return Credibility.AUTH_AUTHORITY;
		else
			return Credibility.NONAUTH_AUTHORITY;
	} else if (section == Section.ADDITIONAL) {
		return Credibility.ADDITIONAL;
	} else
		throw new IllegalArgumentException("getCred: invalid section");
}
Looks up Records in the Cache (a wrapper around lookupRecords).  Unlike
lookupRecords, this given no indication of why failure occurred.
@param name The name to look up
@param type The type to look up
@return An array of RRsets, or null
@see Credibility
src/main/java/core/org/xbill/DNS/Cache.java