static void registerType(PrimitiveTypeEntry t) {
    if (t.primitiveCategory != PrimitiveCategory.UNKNOWN) {
      primitiveCategoryToTypeEntry.put(t.primitiveCategory, t);
    }
    if (t.primitiveJavaType != null) {
      primitiveJavaTypeToTypeEntry.put(t.primitiveJavaType, t);
    }
    if (t.primitiveJavaClass != null) {
      primitiveJavaClassToTypeEntry.put(t.primitiveJavaClass, t);
    }
    if (t.primitiveWritableClass != null) {
      primitiveWritableClassToTypeEntry.put(t.primitiveWritableClass, t);
    }
    if (t.typeName != null) {
      typeNameToTypeEntry.put(t.typeName, t);
    }
  }
typeName is the name of the type as in DDL.
serde/src/java/org/apache/hadoop/hive/serde2/objectinspector/primitive/PrimitiveObjectInspectorUtils.java