purejson

Pure Functional Json Parser Library.

Built on top of Gson minimal-json parser, it defines an encoder/decoder machinery.

It supports java records and the minimum required java version is Java 17.

Usage

If you are familiar with Gson, it will be pretty straightforward for you to use this library.

  record User(int id, String name) {}

  var json = """
     { "id": 1, "name": "toni" }
     """.strip();

  var user = new PureJson<>(User.class).fromJson(json);

  assertEquals(new User(1, "toni"), user);

PureJson supports runtime reflection and annotation processors. If an adapter exists for a specific type, then the adapter is used instead of reflection.

Features

Runtime Reflection

• Java POJOs: with empty constructor and setter/getters. Fields are populated using reflection.
• Java Value Objects: without empty constructor and setters (immutables). Constructor with parameters is used to create new instances.
• Java Records (Java 17+): canonical constructor is used to create new instances.

Annotation Processor

You can annotate your classes with @Json and an adapter for this class will be generated.

• Java Value Objects
• Java Records (Java 17+)

Performance

Tested on my laptop:

• cpu: Intel Core i7-1165G7
• ram: 64GB
• cores: 8

Performance parse pojo
name  tot   min max mean  p50 p90 p95 p99
refl  60349 9   59  12    11  13  15  23
buil  16858 2   39  3     2   5   5   7
adho  14996 2   38  2     2   4   5   6
gson  10485 1   36  2     1   3   3   4

Performance parse record
name  tot   min max mean p50 p90 p95 p99
refl  16542 2   50  3    2   5   5   6
buil  16306 2   50  3    2   5   5   6
adho  17670 2   51  3    3   3   5   7
gson  13903 2   50  2    2   3   5   5

Performance serialize pojo
name  tot   min max mean p50 p90 p95 p99
refl  31824 5   22  6    6   6   8   11
buil  34202 3   25  6    6   10  11  12
adho  32495 4   21  6    6   7   10  11
gson  26533 4   18  5    5   6   6   6

Performance serialize record
name  tot   min max mean p50 p90 p95 p99
refl  33065 4   23  6    6   8   10  12
buil  33042 4   24  6    6   8   10  12
adho  32888 5   23  6    5   8   10  12
gson  27768 4   25  5    5   6   6   6