@Override
  public boolean equals(Object obj) {
    if (obj == null) {
      return false;
    }
    if (getClass() != obj.getClass()) {
      return false;
    }
    PrimitiveTypeInfo other = (PrimitiveTypeInfo) obj;
    if (typeName == null) {
      if (other.typeName != null) {
        return false;
      }
    } else if (!typeName.equals(other.typeName)) {
      return false;
    }
    return true;
  }
Returns the category of this TypeInfo.
serde/src/java/org/apache/hadoop/hive/serde2/typeinfo/PrimitiveTypeInfo.java