cachedEncoder = null; cachedDecoder = null;
  protected Charset (String canonicalName, String[] aliases)  {    checkName (canonicalName);    if (aliases != null)      {			int n = aliases.length;			for (int i = 0; i < n; ++i)            checkName (aliases[i]);		}		this.canonicalName = canonicalName;		this.aliases = aliases;	}