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Jackson vs Gson: Which Should You Choose?

The definitive comparison of Java's two most popular JSON libraries. Performance, features, and real-world recommendations.

TL;DR Quick Answer

Use Jackson if:

  • • Spring Boot / Spring MVC app
  • • Need streaming for large files
  • • Complex annotation needs
  • • Performance is critical

Use Gson if:

  • • Simple Android project
  • • Want minimal dependencies
  • • Need easy setup
  • • Small JSON payloads only

Feature Comparison

FeatureJacksonGson
Performance⚡ FastestGood
Streaming API
Spring Boot Default
Android Size~1.5 MB~250 KB
Kotlin SupportVia moduleUnsafe
Learning CurveModerateEasy
Annotation@JsonProperty@SerializedName

Code Comparison

Jackson

ObjectMapper mapper = new ObjectMapper();

// JSON to POJO
User user = mapper.readValue(
    json, User.class);

// POJO to JSON
String json = mapper
    .writeValueAsString(user);

Gson

Gson gson = new Gson();

// JSON to POJO
User user = gson.fromJson(
    json, User.class);

// POJO to JSON
String json = gson.toJson(user);

Performance Benchmarks

Based on JMH benchmarks (operations per second, higher is better):

Jackson~50,000 ops/sec
Gson~35,000 ops/sec

* Results vary by JSON complexity and JVM version. Jackson is consistently 30-50% faster.

Our Recommendation

Choose Jackson For:

  • Spring Boot applications
  • High-throughput APIs
  • Large JSON files (streaming)
  • Complex polymorphic types
→ Read Jackson Guide

Choose Gson For:

  • Simple Android apps
  • Quick prototypes
  • Minimal dependency size
  • Beginner-friendly setup
→ Read Gson Guide

For Kotlin/Android?

Skip both. Use kotlinx.serialization or Moshi instead. They handle Kotlin null safety correctly, which Gson cannot.

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