Revolutionize JSON Parsing in Java With Manifold

Java builders have usually envied JavaScript for its ease of parsing JSON. Though Java gives extra robustness, it tends to contain extra work and boilerplate code. Due to the Manifold mission, Java now has the potential to outshine JavaScript in parsing and processing JSON information. Manifold is a revolutionary set of language extensions for Java that fully modifications the way in which we deal with JSON (and rather more).
Modern Java: Make Java JSON Manifold, Part 1

Getting Began With Manifold

The code for this tutorial might be discovered on my GitHub page. Manifold is comparatively younger however already huge in its capabilities. You possibly can study extra concerning the mission on their web site and Slack channel. To start, you may want to put in the Manifold plugin, which is at the moment solely obtainable for JetBrains IDEs. The mission helps LTS releases of Java, together with the newest JDK 19.

We are able to set up the plugin from IntelliJ/IDEAs settings UI by navigating to {the marketplace} and trying to find Manifold. The plugin makes certain the IDE doesn’t collide with the work accomplished by the Maven/Gradle plugin.

Manifold plugin

Manifold consists of a number of smaller tasks, every providing a customized language extension. At this time, we’ll talk about one such extension, however there’s rather more to discover.

Setting Up a Maven Undertaking

To exhibit Manifold, we’ll use a easy Maven mission (it additionally works with Gradle). We first want to stick the present Manifold model from their web site and add the required dependencies. The primary dependency for JSON is the manifold-json-rt dependency. Different dependencies might be added for YAML, XML, and CSV help. We have to add this to the pom.xml file within the mission.

I am conscious of the irony the place the boilerplate discount for JSON begins with quite a lot of configuration within the Maven construct script. However that is configuration, not “precise code” and it is largely copy and paste. Discover that if you wish to scale back this code the Gradle equal code is terse by comparability.

This line wants to enter the properties part:


The dependencies we use are these:


The compilation plugin is the boilerplate that weaves Manifold into the bytecode and makes it seamless for us. It’s the final a part of the pom setup:

                   <!-- Configure manifold plugin-->

               <!-- Add the processor path for the plugin -->

With the setup full, let’s dive into the code.

Parsing JSON With Manifold

We place a pattern JSON file within the mission listing below the assets hierarchy. I positioned this file below src/most important/assets/com/debugagent/json/Take a look at.json:

  "firstName": "Shai",
  "surname": "Almog",
  "web site": "",
  "energetic": true,
    "key": "value"

In the principle class, we refresh the Maven mission, and you will discover a brand new Take a look at class seems. This class is dynamically created by Manifold based mostly on the JSON file. When you change the JSON and refresh Maven, all the things updates seamlessly. It’s vital to grasp that Manifold isn’t a code generator. It compiles the JSON we simply wrote into bytecode.

The Take a look at class comes with a number of built-in capabilities, corresponding to a type-safe builder API that allows you to assemble JSON objects utilizing builder strategies. You may also generate nested objects and convert the JSON to a string through the use of the write() and toJson() strategies.

It means we are able to now write:

Take a look at check = Take a look at.builder().withFirstName("Somebody")
                Take a look at.particulars.detailsItem.builder().
                        withKey("Worth 1").construct()

Which is able to printout the next JSON:

  "firstName": "Somebody",
  "surname": "Surname",
  "energetic": true,
  "particulars": [
      "key": "Value 1"

We are able to equally learn a JSON file utilizing code corresponding to this:

Take a look at readObject = Take a look at.load().fromJson("""
          "firstName": "Somebody",
          "surname": "Surname",
          "energetic": true,
          "particulars": [
              "key": "Value 1"

Word using Java 15 TextBlock syntax for writing an extended string. The load() technique returns an object that features numerous APIs for studying the JSON. On this case, it’s learn from a String however there are APIs for studying it from a URL, file, and so forth.

Manifold helps numerous codecs, together with CSV, XML, and YAML, permitting you to generate and parse any of those codecs with out writing any boilerplate code or sacrificing sort security. So as to add that help we might want to add further dependencies to the pom.xml file:


With these further dependencies, this code will print out the identical information because the JSON file. With check.write().toCsv() the output could be:


Discover that the Comma Separated Values (CSV) output doesn’t embrace hierarchy info. That’s a limitation of the CSV format and never the fault of Manifold.

With check.write().toXml() the output is acquainted and surprisingly concise:

<root_object firstName="Somebody" surname="Surname" energetic="true">
  <particulars key="Worth 1"/>

With check.write().toYaml() we once more get a well-known printout:

firstName: Somebody
surname: Surname
energetic: true
- key: Worth 1

Working With JSON Schema

Manifold additionally works seamlessly with JSON schema, permitting you to implement strict guidelines and constraints. That is notably helpful when working with dates and enums. Manifold seamlessly creates/updates byte code that adheres to the schema, making it a lot simpler to work with complicated JSON information.

This schema is copied and pasted from the Manifold GitHub project:

  "$schema": "",
  "$id": "",
  "sort": "object",
      "sort": "string",
      "enum": ["male", "female"]
      "sort": "string",
      "description": "Person's full title.",
      "maxLength": 80
    "e mail": 
      "description": "Person's e mail.",
      "sort": "string",
      "format": "e mail"
      "sort": "string",
      "description": "Date of makes use of beginning within the one and solely date customary: ISO 8601.",
      "format": "date"
      "$ref" : "#/definitions/Gender"
  "required": ["name", "email"]

It’s a comparatively easy schema, however I’d like to show your consideration to a number of issues right here. It defines title and e mail as required. This is the reason after we attempt to create a Person object utilizing a builder in Manifold, the construct() technique requires each parameters:

Person.builder("Identify", "e [email protected]")   

That’s simply the beginning. The schema features a date. Dates are a painful prospect in JSON, the standardization is poor and fraught with points. The schema additionally features a gender subject which is successfully an enum. That is all transformed to type-safe semantics utilizing widespread Java courses corresponding to LocalDate:

Person u = Person.builder("Identify", "e [email protected]")
       .withDate_of_birth(LocalDate.of(1999, 10, 11))

That may be made even shorter with static imports however the gist of the concept is obvious. JSON is successfully native to Java in Manifold.


The Tip of The Iceberg

Manifold is a strong and thrilling mission. It revolutionizes JSON parsing in Java however that’s only one tiny portion of what it might probably do!

We have solely scratched the floor of its capabilities on this submit. Within the subsequent article, we’ll dive deeper into Manifold and discover some further surprising options.

Please share your expertise and ideas about Manifold within the feedback part. When you’ve got any questions, do not hesitate to ask.