b.java

public class ATest {

    @Test
    public void test() {
        JSONObject root = new JSONObject("{}");
        List<TestC> list = new ArrayList<>();
        TestC testC = new TestC("type", "bucket", "code", null, DateTime.now(),
            null);
        TestC testC1 = new TestC("type", "bucket", "code", null, DateTime.now(),
            null);

        root.put("1", testC);

        list.add(testC);
        list.add(testC1);

        root.put("2", list);
    }

    private static class TestC {

        private final String id;
        private final String bucket;
        private final String type;
        private final String code;
        private Map<String, String> fields;
        private List<String> tags;
        private DateTime time;

        private Long version;


        public TestC(String type, String bucket, String code, Map<String, String> fields, DateTime time,
                     List<String> tags) {

            if (bucket == null || bucket.isEmpty() || bucket.contains("-")) {
                throw new IllegalArgumentException("bucket cannot be null, empty and cannot contain the '-' character.");
            }

            if (type == null || type.isEmpty() || type.contains("-")) {
                throw new IllegalArgumentException("type cannot be null, empty and cannot contain the '-' character.");
            }

            if (code == null || code.isEmpty()) {
                throw new IllegalArgumentException("code cannot be null, empty.");
            }

            if (fields == null) {
                fields = new HashMap<>();
            }

            if (time == null) {
                time = DateTime.now().withZone(DateTimeZone.UTC);
            }

            if (tags == null) {
                tags = new ArrayList<>();
            }

            this.id = createId(bucket, type, code);
            this.type = type;
            this.bucket = bucket;
            this.code = code;
            this.fields = fields;
            this.time = time;
            this.tags = tags;
        }

        public static String createId(String bucket, String type, String code) {
            return bucket + "-" + type + "-" + code;
        }

        public String getId() {
            return id;
        }

        public String getBucket() {
            return bucket;
        }

        public String getType() {
            return type;
        }

        public String getCode() {
            return code;
        }

        public Map<String, String> getFields() {
            return fields;
        }

        public void setFields(Map<String, String> fields) {
            this.fields = fields;
        }

        public List<String> getTags() {
            return tags;
        }

        public void setTags(List<String> tags) {
            this.tags = tags;
        }

        public DateTime getTime() {
            return time;
        }

        public void setTime(DateTime time) {
            this.time = time;
        }

        public Long getVersion() {
            return version;
        }

        public void setVersion(Long version) {
            this.version = version;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) {
                return true;
            }
            if (o == null || getClass() != o.getClass()) {
                return false;
            }
            TestC testC = (TestC) o;
            return Objects.equals(getId(), testC.getId()) &&
                Objects.equals(getBucket(), testC.getBucket()) &&
                Objects.equals(getType(), testC.getType()) &&
                Objects.equals(getCode(), testC.getCode()) &&
                Objects.equals(getFields(), testC.getFields()) &&
                Objects.equals(getTags(), testC.getTags()) &&
                Objects.equals(getTime(), testC.getTime()) &&
                Objects.equals(getVersion(), testC.getVersion());
        }

        @Override
        public int hashCode() {
            return Objects.hash(getId(), getBucket(), getType(), getCode(), getFields(), getTags(), getTime(), getVersion());
        }

        @Override
        public String toString() {
            return "TestC{" +
                "id='" + id + '\'' +
                ", bucket='" + bucket + '\'' +
                ", type='" + type + '\'' +
                ", code='" + code + '\'' +
                ", fields=" + fields +
                ", tags=" + tags +
                ", time=" + time +
                ", version=" + version +
                '}';
        }
    }
}