AttributeReader(Name name,
    Version version,
    Set<AttributeKind> kinds) 
{
            this.name = name;
            this.version = version;
            this.kinds = kinds;
}

 boolean accepts(AttributeKind kind) 
{
            if (kinds.contains(kind)) {
                if (majorVersion  > version.major || (majorVersion == version.major && minorVersion  >= version.minor))
                    return true;
                if (lintClassfile && !warnedAttrs.contains(name)) {
                    JavaFileObject prev = log.useSource(currentClassFile);
                    try {
                        log.warning(LintCategory.CLASSFILE, (DiagnosticPosition) null, "future.attr",
                                name, version.major, version.minor, majorVersion, minorVersion);
                    } finally {
                        log.useSource(prev);
                    }
                    warnedAttrs.add(name);
                }
            }
            return false;
}

 abstract  void read(Symbol sym,
    int attrLen)