apache/dolphinscheduler · error · IllegalArgumentException

Object: + obj + to json serialization exception.

Error message

Object: + obj + to json serialization exception.

What it means

JSONUtils.toJsonByteArray converts an arbitrary Java object to a UTF-8 JSON byte array. Any exception thrown by the underlying Jackson serialization (via toJsonString/objectMapper) is wrapped in an IllegalArgumentException whose message echoes the offending object. It signals the object graph is not JSON-serializable rather than a caller input-format problem.

Source

Thrown at dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/JSONUtils.java:332

            throw new RuntimeException("Object json deserialization exception.", e);
        }
    }

    /**
     * serialize to json byte
     *
     * @param obj object
     * @param <T> object type
     * @return byte array
     */
    public static <T> byte[] toJsonByteArray(T obj) {
        if (obj == null) {
            return null;
        }
        try {
            return toJsonString(obj).getBytes(UTF_8);
        } catch (Exception e) {
            throw new IllegalArgumentException("Object: " + obj + " to json serialization exception.", e);
        }

    }

    public static ObjectNode parseObject(String text) {
        try {
            if (StringUtils.isEmpty(text)) {
                return parseObject(text, ObjectNode.class);
            } else {
                return (ObjectNode) objectMapper.readTree(text);
            }
        } catch (Exception e) {
            throw new RuntimeException("String json deserialization exception.", e);
        }
    }

    public static ArrayNode parseArray(String text) {
        try {

View on GitHub (pinned to 02eac45a1b)

Solutions

1. Print/inspect the wrapped cause (e.getCause()) to find the exact failing property or type
2. Annotate unserializable fields with @JsonIgnore or mark them transient and add getters Jackson can see
3. Break cyclic references with @JsonManagedReference/@JsonBackReference or set SerializationFeature.FAIL_ON_SELF_REFERENCES appropriately
4. Register a custom JsonSerializer/Module for third-party types that Jackson cannot handle
5. Ensure the object is a plain POJO (no-arg constructor + getters) or convert it to a Map before serializing

Example fix

// before
byte[] data = JSONUtils.toJsonByteArray(taskExecutionContext.getInjectedStream());
// after
@JsonIgnore
private transient InputStream rawStream; // exclude non-serializable field

if (obj == null) return null; // also ensure fields are Jackson-friendly: no cycles, no raw streams

boolean isSerializable(Object o) {
  try { JSONUtils.toJsonString(o); return true; } catch (Exception e) { return false; }
}

try {
  byte[] data = JSONUtils.toJsonByteArray(obj);
} catch (IllegalArgumentException e) {
  log.error("Unserializable object of type {}: {}", obj.getClass().getName(), e.getCause());
  throw new IllegalStateException("Object not serializable to JSON", e);
}

When it happens

Trigger: Calling JSONUtils.toJsonByteArray(obj) when Jackson fails on the object: no accessible getters/fields, infinite recursion from cyclic references, unserializable types (InputStream, Thread), a property getter that throws, or invalid ObjectMapper configuration

Common situations: Putting a non-POJO (e.g. an Hadoop Configuration, a lambda, an open stream) into a task parameter or workflow context that is later serialized to JSON; adding a getter with side effects or a self-referencing object graph after a version upgrade.

Understand the failure class

Background: "JSON serialization failed", "not JSON serializable", "Failed to serialize": why JSON marshaling errors happen and how to fix them — this error's family across 46 libraries.

Related errors

• Object json deserialization exception.
• Class type cannot be null
• Parse json: <json> to class: <clazz> failed
• String json deserialization exception.
• Json deserialization exception.

AI-assisted analysis of apache/dolphinscheduler@02eac45a1b (2026-09-06). Data as JSON: /api/errors/7aa20e3ad42ec548. Report an issue: GitHub.