Group JSON array data and count it if have two same value

Your question can be considered as "Count the number of occurrences of an element in a list grouping by fields kecamatan and desa".
Therefore, if you can convert the given JSON string to a list of object such as a List<Data>, then you can count the number of occurrences with Stream and Lambda Expression (since Java 8) as follows:

POJOs

class MyDatas {
    private List<MyData> data;

    //general getters and setters
}

@JsonIgnoreProperties(ignoreUnknown = true)
class MyData {
    private String kecamatan;
    private String desa;

    public String getGroupBy() {
        return String.format("%s [%s]", this.getKecamatan(), this.getDesa());
    }

    //general getters and setters
}

For class MyData, I create a method getGroupBy() which return the key for grouping.

Code snippet

ObjectMapper mapper = new ObjectMapper();
MyDatas myDatas = mapper.readValue(jsonStr, MyDatas.class);
Map<String, Long> counting = myDatas.getData()
        .stream()
        .collect(Collectors.groupingBy(
                MyData::getGroupBy, Collectors.counting()));
System.out.println(counting);

Use Jackson to convert the JSON string to POJO first, then use Collectors.groupingBy() to count the number of occurrences with MyData::getGroupBy.

Console output

{Bontomantene [Garaupa]=1, Benteng [Benteng Selatan]=2, Benteng [Benteng Utara]=1}