A: B: BA: value BB: value BC: value C: CA: value CB: value D: DA: value DB: value DC: DCA: value DCB: value
String dca_value = map.get("A").get("D").get("DC").get("DCB");
Map map_A = (Map) reader.read();
Map map_D = (Map) map_a.get("D");
Map map_DC = (Map) map_d.get("DC");
String dca_value = (String) map_dc.get("DCA");