public Throwable getThrowable(Object[] args) {
    Throwable rv = null;
    if (args.length > 0) {
      if (args[args.length - 1] instanceof Throwable) {
        rv = (Throwable) args[args.length - 1];
      }
    }
    return rv;
  }
Get the throwable from the last element of this array if it is Throwable,
else null.
src/main/java/net/spy/memcached/compat/log/AbstractLogger.java