code: private boolean[] mapNullableColumns(TableColumnInfo tableMetadata)
      {
          boolean[] nullableColumns = new boolean[this.columns.length];
  
          for (int i = 0; i < this.columns.length; i++)
          {
              String column = columns[i];
              nullableColumns[i] = tableMetadata.getColumn(column).isNullable();
          }
  
          return nullableColumns;
      }
docs: Maps which columns accept <code>null</code> and which don't.
  @param tableMetadata The metadata about the table.
  @return An array of the size of the number of columns with <code>true</code> set if the column is nullable.