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 i7-1065G7 @ 8x 3.9GHz
• ram: 32GB
• cores: 4

Performance parse pojo
name  tot   min max mean  p50 p90 p95 p99 rps
refl  37575 5   124 7     6   8   9   25  133
buil  21722 3   108 4     3   4   5   8   230
adho  19488 2   107 3     3   4   5   7   256
gson  13707 1   103 2     2   2   3   6   364

Performance parse record
name  tot   min max mean  p50 p90 p95 p99 rps
refl  16017 1   174 3     2   3   5   5   312
buil  16382 1   175 3     2   4   5   6   305
adho  18214 1   176 3     2   3   5   6   274
gson  15766 1   172 3     2   4   5   5   317

Performance serialize pojo
name  tot   min max mean  p50 p90 p95 p99 rps
refl  26114 3   617 5     3   6   7   28  191
buil  26299 2   614 5     3   6   8   21  190
adho  24785 3   152 4     3   6   7   18  201
gson  31217 3   619 6     5   6   7   25  160

Performance serialize record
name  tot   min max mean  p50 p90 p95 p99 rps
refl  29586 2   361 5     3   7   8   15  168
buil  28702 3   360 5     3   7   7   15  174
adho  28602 3   360 5     3   7   7   14  174
gson  33846 3   360 6     5   7   7   16  147