Java Lambda

Map<String, String> insured = Stream.of("Adults:1", "Children:1", "Senior Citizen:10")
                                    .map(pair -> pair.split(":"))
                                    .collect(Collectors.toMap(pair -> pair[0], pair->pair[1]));

Double totalInsured = insured.values().stream().mapToDouble(d -> Double.parseDouble(d)).sum();
Double totalInsured = insured.values().stream().mapToDouble(Double::parseDouble).sum();

Integer totalInsured = insured.values().stream().mapToInt(d -> Integer.parseInt(d)).sum();
Integer totalInsured = insured.values().stream().mapToInt(Integer::parseInt).sum();

Map<String, String> mapping = Stream.of("travel_adult:Adults", "travel_children:Children", "travel_senior_citizen:Senior Citizen")
                                    .map(pair -> pair.split(":"))
                                    .collect(Collectors.toMap(pair -> pair[0], pair->pair[1]));

Map<String, String> reverse = mapping.entrySet().stream()
                                     .collect(Collectors.toMap(map -> map.getValue(), map -> map.getKey()));

References

Sum values in a Map with a stream