jackson-core

Incremental (streaming) processing is performed using two main abstractions:

• JsonParser: Used for reading JSON data. Instances are constructed by a JsonFactory.
• JsonGenerator: Used for writing JSON data. Instances are constructed by a JsonFactory.

Note: While the core abstractions are not JSON-specific, the default implementation provided in this package handles the JSON format.

The JsonFactory is a reusable and thread-safe instance used to create parsers and generators. Since Jackson 2.10, it is recommended to use the builder pattern for configuration.

If you are already using the jackson-databind package, you can retrieve the factory from an existing ObjectMapper using tokenStreamFactory().

// Builder-style since 2.10:
JsonFactory factory = JsonFactory.builder()
// configure, if necessary:
     .enable(JsonReadFeature.ALLOW_JAVA_COMMENTS)
     .build();

// Alternatively, from an ObjectMapper:
JsonFactory factory = objectMapper.tokenStreamFactory();

Depending on the version of Jackson you are using, the groupId and package names differ. Use the following dependencies for Maven projects:

Jackson 3.x

• Group ID: tools.jackson.core
• Artifact ID: jackson-core

Jackson 2.x

• Group ID: com.fasterxml.jackson.core
• Artifact ID: jackson-core

<dependency> <!-- Jackson 3.x -->
    <groupId>tools.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>3.2.1</version>
</dependency>
<dependency> <!-- Jackson 2.x -->
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.21.5</version>
</dependency>

Starting with Jackson 2.15, you can configure limits to reduce the risk of excessive memory usage or processing costs. These limits are configured on a per-JsonFactory basis using StreamReadConstraints and StreamWriteConstraints.

JsonFactory f = JsonFactory.builder()
  .streamReadConstraints(StreamReadConstraints.builder().maxDocumentLength(10_000_000L).build())
  .streamReadConstraints(StreamReadConstraints.builder().maxNumberLength(250).build())
  .streamWriteConstraints(StreamWriteConstraints.builder().maxNestingDepth(2000).build())
  .build();

Starting with Jackson 2.16, you can configure how much content is included in error messages to prevent massive error strings.

JsonFactory f = JsonFactory.builder()
 .errorReportConfiguration(ErrorReportConfiguration.builder()
   .maxErrorTokenLength(1004)
   .maxRawContentLength(2008)
   .build()
 ).build();

Ensure your environment meets the minimum requirements for the version of jackson-core you are using.

JDK Requirements

• 2.14 and above: JDK 8+
• 3.0 and above: JDK 17+

Android Requirements

• 2.14 and above: Android SDK 26+
• 3.0 and above: Android SDK 26+