{"record":{"id":"295d4a514a9cf0b2","repo":"FasterXML/jackson-databind","slug":"cannot-use-formatschema-of-type-for-format-295d4a","errorCode":null,"errorMessage":"Cannot use FormatSchema of type {} for format {}","messagePattern":"Cannot use FormatSchema of type (.+?) for format (.+?)","errorType":"exception","errorClass":"IllegalArgumentException","httpStatus":null,"severity":"error","filePath":"src/main/java/tools/jackson/databind/ObjectWriter.java","lineNumber":1279,"sourceCode":"    /**\n     * Overridable helper method used for constructing\n     * {@link SerializationContext} to use for serialization.\n     */\n    protected final SerializationContextExt _serializationContext() {\n        return _serializationContexts.createContext(_config, _generatorSettings);\n    }\n\n    /*\n    /**********************************************************************\n    /* Internal methods\n    /**********************************************************************\n     */\n\n    protected void _verifySchemaType(FormatSchema schema)\n    {\n        if (schema != null) {\n            if (!_generatorFactory.canUseSchema(schema)) {\n                    throw new IllegalArgumentException(\"Cannot use FormatSchema of type \"+schema.getClass().getName()\n                            +\" for format \"+_generatorFactory.getFormatName());\n            }\n        }\n    }\n\n    /**\n     * Helper method that applies configured {@link GeneratorInitializer},\n     * if any, to the given generator and returns it.\n     *\n     * @since 3.2\n     */\n    protected JsonGenerator _initializeGenerator(JsonGenerator gen) {\n        GeneratorInitializer init = _config.getGeneratorInitializer();\n        if (init != null) {\n            init.initialize(_config, gen);\n        }\n        return gen;\n    }","sourceCodeStart":1261,"sourceCodeEnd":1297,"githubUrl":"https://github.com/FasterXML/jackson-databind/blob/87876ca5c0569b4933aec2d30d6225e4b9ba3a43/src/main/java/tools/jackson/databind/ObjectWriter.java#L1261-L1297","documentation":"Thrown by ObjectWriter._verifySchemaType() when a FormatSchema is set on the writer but the underlying generator factory cannot use it. Each format has its own schema type; passing a schema from a different format is a type mismatch. The check uses the generator factory's canUseSchema() method.","triggerScenarios":"Calling writer.with(schema) where schema is, e.g., a CsvSchema but the writer is backed by a JsonFactory. Same mismatch issue as the reader side but on the serialization path.","commonSituations":"Using a JSON ObjectMapper to write CSV or YAML with a format-specific schema. Copy-pasting schema code between format contexts. Module configuration that replaces the default factory.","solutions":["Use the format-specific mapper: new CsvMapper().writer(schema).writeValue(...).","Verify the writer's factory getFormatName() matches the schema's expected format before calling with(schema).","Construct the writer from the same format-specific mapper that produced the schema."],"exampleFix":"// before\nObjectWriter w = jsonMapper.writer(csvSchema); // throws\n// after\nObjectWriter w = csvMapper.writer(csvSchema);","handlingStrategy":"validation","validationCode":"// Check schema compatibility before setting\nif (schema != null && !writer._generatorFactory.canUseSchema(schema)) {\n    throw new IllegalArgumentException(\"Schema incompatible with writer format\");\n}","typeGuard":"boolean schemaMatchesGenerator(JsonFactory factory, FormatSchema schema) {\n    return schema == null || factory.canUseSchema(schema);\n}","tryCatchPattern":null,"preventionTips":["Use the format-specific mapper that matches your schema.","Never cross schema types between formats.","Construct writer and schema from the same format-specific mapper."],"tags":["format-schema","objectwriter","format-mismatch","csv","yaml","configuration"],"backgroundTag":null,"analyzedSha":"87876ca5c0569b4933aec2d30d6225e4b9ba3a43","analyzedAt":"2026-08-11T12:55:24.033Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}