@Override public boolean equals(Object obj) { if (this == obj) { return true; } if (!super.equals(obj)) { return false; } if (getClass() != obj.getClass()) { return false; } RelDataTypeDrillImpl other = (RelDataTypeDrillImpl) obj; if (holder == null) { if (other.holder != null) { return false; } } else if (!holder.equals(other.holder)) { return false; } return true; }