public static DefaultIncompatibleTableChangeHandler get() {
    return INSTANCE;
  }
Default incompatible table change handler. This is invoked by the {@link
HiveAlterHandler} when a table is altered to check if the column type changes if any
are allowed or not.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/DefaultIncompatibleTableChangeHandler.java