private boolean checkPackage(String className, String packageName) {
        if (packages.contains(packageName)) {
            cacheClassname(className);
            return true;
        }
        return false;
    }
private boolean checkPackage ( String className , String packageName ) { if ( packages . contains ( packageName ) ) { cacheClassname ( className ) ; return true ; } return false ; }
Checks if given class name is listed by package. If it's listed, then performance optimization is used and classname is
added directly to {@code classes} collection.

@param className   Class name to be checked.
@param packageName Package name of the checked class.
@return {@code true} iff class is listed by-package