code: public static String getColumnDefaultValue (Connection conn, String table, String column)
          throws SQLException
      {
          ResultSet rs = getColumnMetaData(conn, table, column);
          try {
              return rs.getString("COLUMN_DEF");
          } finally {
              rs.close();
          }
      }
docs: Returns a string representation of the default value for the specified column in the
  specified table. This may be null.