public static class Builder {
        private final Map<String, Object> data;
        public Builder() {
            data = newLinkedHashMap();
        }

        public Builder add(final String key, final Object value) {
            data.put(key, value);
            return this;
        }

        public Builder add(final Object value) {
            data.put(String.valueOf(data.size()), value);
            return this;
        }

        public Builder set(final String path, final Object value) {
            U.set(data, path, value);
            return this;
        }

        public Builder add(final Builder builder) {
            data.put(String.valueOf(data.size()), builder.build());
            return this;
        }

        @SuppressWarnings("unchecked")
        public Map<String, Object> build() {
            return (Map<String, Object>) ((LinkedHashMap) data).clone();
        }

        public String toXml() {
            return Xml.toXml(data);
        }

        public static Builder fromXml(final String xml) {
            final Builder builder = new Builder();
            builder.data.putAll(fromXmlMap(xml));
            return builder;
        }

        public String toJson() {
            return Xml.toXml(data);
        }

        public static Builder fromJson(final String json) {
            final Builder builder = new Builder();
            builder.data.putAll(fromJsonMap(json));
            return builder;
        }

        @Override
        public String toString() {
            return data.toString();
        }
    }

        Map<String, Object> value = U.objectBuilder()
            .add("firstName", "John")
            .add("lastName", "Smith")
            .add("age", 25)
            .add("address", U.arrayBuilder()
                .add(U.objectBuilder()
                    .add("streetAddress", "21 2nd Street")
                    .add("city", "New York")
                    .add("state", "NY")
                    .add("postalCode", "10021")))
            .add("phoneNumber", U.arrayBuilder()
                .add(U.objectBuilder()
                    .add("type", "home")
                    .add("number", "212 555-1234"))
                .add(U.objectBuilder()
                    .add("type", "fax")
                    .add("number", "646 555-4567")))
            .build();
        // {firstName=John, lastName=Smith, age=25, address=[{streetAddress=21 2nd Street,
        // city=New York, state=NY, postalCode=10021}], phoneNumber=[{type=home, number=212 555-1234},
        // {type=fax, number=646 555-4567}]}