code: private ColumnInfo getJoinColumn(TableInfo tableInfo, String joinColumnName, Class columnType)
      {
          ColumnInfo columnInfo = new ColumnInfo();
          columnInfo.setColumnName(joinColumnName);
          columnInfo.setIndexable(true);
  
          IndexInfo indexInfo = new IndexInfo(joinColumnName);
          tableInfo.addToIndexedColumnList(indexInfo);
  
          columnInfo.setType(columnType);
          return columnInfo;
      }
docs: getJoinColumn method return ColumnInfo for the join column
  
  @param columnType
  
  @param String
  joinColumnName.
  @return ColumnInfo object columnInfo.