{"record":{"id":"028c710f9982ba9e","repo":"hibernate/hibernate-orm","slug":"unable-to-instantiate","errorCode":null,"errorMessage":"Unable to instantiate ","messagePattern":"Unable to instantiate ","errorType":"exception","errorClass":"HibernateException","httpStatus":null,"severity":"error","filePath":"hibernate-core/src/main/java/org/hibernate/id/uuid/UuidGenerator.java","lineNumber":149,"sourceCode":"\t\t\t\t\t);\n\t\t\t\t}\n\t\t\t\treturn instantiateCustomGenerator( config.algorithm() );\n\t\t\t}\n\t\t\treturn switch ( style ) {\n\t\t\t\tcase TIME -> new CustomVersionOneStrategy();\n\t\t\t\tcase VERSION_6 -> UuidVersion6Strategy.INSTANCE;\n\t\t\t\tcase VERSION_7 -> UuidVersion7Strategy.INSTANCE;\n\t\t\t\tdefault -> StandardRandomStrategy.INSTANCE;\n\t\t\t};\n\t\t}\n\t}\n\n\tprivate static UuidValueGenerator instantiateCustomGenerator(Class<? extends UuidValueGenerator> algorithmClass) {\n\t\ttry {\n\t\t\treturn algorithmClass.getDeclaredConstructor().newInstance();\n\t\t}\n\t\tcatch (Exception e) {\n\t\t\tthrow new HibernateException( \"Unable to instantiate \" + algorithmClass.getName(), e );\n\t\t}\n\t}\n\n\tprivate ValueTransformer determineProperTransformer(Class<?> propertyType) {\n\t\tif ( UUID.class.isAssignableFrom( propertyType ) ) {\n\t\t\treturn UUIDJavaType.PassThroughTransformer.INSTANCE;\n\t\t}\n\t\telse if ( String.class.isAssignableFrom( propertyType ) ) {\n\t\t\treturn UUIDJavaType.ToStringTransformer.INSTANCE;\n\t\t}\n\t\telse if ( byte[].class.isAssignableFrom( propertyType ) ) {\n\t\t\treturn UUIDJavaType.ToBytesTransformer.INSTANCE;\n\t\t}\n\t\telse {\n\t\t\tthrow new HibernateException( \"Unanticipated return type [\" + propertyType.getName() + \"] for UUID conversion\" );\n\t\t}\n\t}\n}","sourceCodeStart":131,"sourceCodeEnd":167,"githubUrl":"https://github.com/hibernate/hibernate-orm/blob/fad1729dce015f908198d57a8d80274a30f905a5/hibernate-core/src/main/java/org/hibernate/id/uuid/UuidGenerator.java#L131-L167","documentation":"Error \"Unable to instantiate \" thrown in hibernate/hibernate-orm.","triggerScenarios":"Thrown when Hibernate fails to instantiate a configured class (reflection failure).","commonSituations":"Typical situations: the class is not on the classpath; no accessible no-arg constructor; the configured class name is misspelled.","solutions":["Ensure the custom UUID value generator class has a public no-arg constructor and is on the classpath."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"fad1729dce015f908198d57a8d80274a30f905a5","analyzedAt":"2026-08-22T04:13:57.527Z","schemaVersion":2},"datasetVersion":"2026-08-22T09:17:25.309Z"}