Pros of Jackson

• More flexible and feature-rich, supporting various data formats beyond JSON
• Better performance, especially for large datasets
• More customization options and annotations for fine-grained control

Cons of Jackson

• Steeper learning curve due to its extensive feature set
• More complex configuration and setup compared to Gson
• Larger library size, which may impact application size

Code Comparison

Jackson:

ObjectMapper mapper = new ObjectMapper();
MyObject obj = mapper.readValue(jsonString, MyObject.class);
String json = mapper.writeValueAsString(obj);

Gson:

Gson gson = new Gson();
MyObject obj = gson.fromJson(jsonString, MyObject.class);
String json = gson.toJson(obj);

Both libraries offer straightforward serialization and deserialization, but Jackson provides more advanced features and configurations. Gson is simpler to use out of the box, while Jackson offers greater flexibility and performance at the cost of increased complexity.

Jackson is generally preferred for larger, more complex projects that require advanced features and customization. Gson is often chosen for simpler applications or when ease of use is a priority. The choice between the two depends on the specific requirements of your project and the level of control you need over the JSON processing.

Pros of fastjson

• Faster parsing and serialization performance
• Supports more data types and complex object structures
• More flexible configuration options for customization

Cons of fastjson

• Less mature and stable compared to gson
• Potential security vulnerabilities (historically)
• Less documentation and community support

Code Comparison

fastjson:

JSON.parseObject(jsonString, MyClass.class);
String jsonOutput = JSON.toJSONString(myObject);

gson:

Gson gson = new Gson();
MyClass obj = gson.fromJson(jsonString, MyClass.class);
String jsonOutput = gson.toJson(myObject);

Both libraries offer similar basic functionality for JSON parsing and serialization. fastjson tends to have a more concise syntax, while gson provides a more object-oriented approach with the Gson class.

fastjson generally offers better performance, especially for large datasets or complex objects. However, gson is known for its stability, widespread adoption, and better documentation.

When choosing between the two, consider factors such as performance requirements, project complexity, and the need for specific features or customizations. gson might be preferable for simpler projects or those prioritizing stability, while fastjson could be advantageous for high-performance scenarios or projects requiring advanced features.

Pros of Moshi

• Better performance, especially for large JSON payloads
• Built-in Kotlin support with codegen for creating type-safe adapters
• More flexible API for custom adapters and annotations

Cons of Moshi

• Smaller community and ecosystem compared to Gson
• Steeper learning curve for advanced features
• Less documentation and fewer examples available online

Code Comparison

Gson:

Gson gson = new Gson();
User user = gson.fromJson(jsonString, User.class);
String json = gson.toJson(user);

Moshi:

val moshi = Moshi.Builder().build()
val adapter = moshi.adapter(User::class.java)
val user = adapter.fromJson(jsonString)
val json = adapter.toJson(user)

Both libraries offer similar basic functionality for JSON serialization and deserialization. Gson provides a simpler API out of the box, while Moshi requires a bit more setup but offers more flexibility and better performance in many cases. Moshi's Kotlin support is a significant advantage for Kotlin developers, while Gson's larger ecosystem and extensive documentation make it easier for beginners to get started.

Pros of json-iterator/java

• Significantly faster performance, especially for large JSON payloads
• More memory-efficient, with lower allocation rates
• Supports streaming for handling very large JSON files

Cons of json-iterator/java

• Less mature and less widely adopted compared to gson
• Fewer built-in type adapters and customization options
• May require more manual configuration for complex use cases

Code Comparison

gson:

Gson gson = new Gson();
MyObject obj = gson.fromJson(jsonString, MyObject.class);
String json = gson.toJson(obj);

json-iterator/java:

JsonIterator iter = JsonIterator.parse(jsonString);
MyObject obj = iter.read(MyObject.class);
String json = JsonStream.serialize(obj);

Both libraries offer similar ease of use for basic JSON serialization and deserialization. However, json-iterator/java provides additional methods for performance optimization, such as using byte arrays directly:

byte[] bytes = jsonString.getBytes();
MyObject obj = JsonIterator.deserialize(bytes, MyObject.class);

While gson is more established and feature-rich, json-iterator/java offers superior performance for high-throughput applications. The choice between the two depends on specific project requirements, with gson being more suitable for general use cases and json-iterator/java excelling in performance-critical scenarios.

Pros of JSON-java

• Lightweight and simple to use, with a straightforward API
• No external dependencies, making it easy to integrate into projects
• Supports both JSON parsing and generation

Cons of JSON-java

• Less feature-rich compared to Gson, lacking advanced serialization/deserialization options
• Not as actively maintained, with fewer updates and contributions
• Limited support for custom type adapters and complex object mapping

Code Comparison

JSON-java:

JSONObject obj = new JSONObject();
obj.put("name", "John");
obj.put("age", 30);
String jsonString = obj.toString();

Gson:

Gson gson = new Gson();
Person person = new Person("John", 30);
String jsonString = gson.toJson(person);

Summary

JSON-java is a simple, lightweight library for JSON processing in Java, while Gson offers more advanced features and better object mapping capabilities. JSON-java is suitable for basic JSON operations, but Gson provides more flexibility and power for complex use cases. The choice between the two depends on the specific requirements of your project and the level of JSON manipulation needed.