@Override
  public int hashCode() {
    //result could be cached if this object were to be made immutable... 
    int result = 17;
    result = 31 * result + (category == null ? 0 : category.hashCode());
    result = 31 * result + (fieldName == null ? 0 : fieldName.hashCode());
    result = 31 * result + (getTypeString() == null ? 0 : 
        getTypeString().hashCode());
    return result;
  }
@deprecated as of 0.13, slated for removal with 0.15
use {@link #getMapKeyTypeInfo()} instead
hcatalog/core/src/main/java/org/apache/hive/hcatalog/data/schema/HCatFieldSchema.java