hibernate/hibernate-orm · error · UnsupportedOperationException

Unsupportd source type

Error message

Unsupportd source type 

What it means

FormatMapper.readFromSource is the streaming-read counterpart of writeToTarget: it deserializes an aggregate directly from a source object (e.g. Oracle's OracleJsonParser for binary OSON), with supportsSourceType advertising capability. The default implementation throws UnsupportedOperationException 'Unsupportd source type ' + source.getClass() (typo present in Hibernate's message) when the configured mapper does not override it for that source type.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/type/format/FormatMapper.java:70

	default boolean supportsSourceType(Class<?> sourceType) {
		return false;
	};

	/**
	 * Checks that this mapper supports a type as a target type.
	 * @param targetType the target type
	 * @return <code>true</code> if the type is supported, false otherwise.
	 */
	default boolean supportsTargetType(Class<?> targetType) {
		return false;
	}

	default <T> void writeToTarget(T value, JavaType<T> javaType, Object target, WrapperOptions options) throws IOException {
		throw new UnsupportedOperationException( "Unsupportd target type " + target.getClass() );
	};

	default <T> T readFromSource(JavaType<T> javaType, Object source, WrapperOptions options) throws IOException {
		throw new UnsupportedOperationException( "Unsupportd source type " + source.getClass() );
	};
}

View on GitHub (pinned to fad1729dce)

Solutions

1. Override readFromSource (and supportsSourceType) in your FormatMapper for the source types Hibernate passes
2. Use the built-in mapper matching the source - the Oracle OSON mapper for OracleJsonParser, Jackson mapper for String/Reader
3. Keep the format mapper configuration aligned with the dialect's JSON storage format

Example fix

// before
FormatMapper mapper = new JacksonJsonFormatMapper(); // supports only CharSequence sources
// Oracle OSON read path hands over OracleJsonParser -> 'Unsupportd source type'

// after
SessionFactoryBuilder cfg = ...;
cfg.applyJsonFormatMapper(new OsonFormatMapper()); // built-in mapper that reads OracleJsonParser

FormatMapper mapper = sessionFactory.getSessionFactoryOptions().getJsonFormatMapper();
if (!mapper.supportsSourceType(OracleJsonParser.class)) {
    // fall back to string-based reading
    T v = mapper.fromString((CharSequence) stringSource, javaType, options);
}

When it happens

Trigger: The ORM reads a JSON aggregate from a non-CharSequence source while the configured FormatMapper only implements fromString - e.g. Oracle OSON handing an OracleJsonParser to a Jackson-based custom mapper, or a custom FormatMapper that predates the readFromSource API.

Common situations: Custom FormatMapper registrations (hibernate.type.json_format_mapper) that only implemented the string API; Oracle binary JSON columns with a third-party mapper; upgrading Hibernate versions where reads switched to readFromSource.

Related errors

• Unsupportd target type
• No more item in JSON document
• Unknown OSON event: {}
• no object key available
• Unsupported numeric type: {}

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/a90f582ba05e8fa4. Report an issue: GitHub.