{"record":{"id":"9865631d98141d80","repo":"apache/pulsar","slug":"an-error-occurred-while-processing-the-field-f","errorCode":null,"errorMessage":"An error occurred while processing the field: ${f.getName()}","messagePattern":"An error occurred while processing the field: (.+?)","errorType":"exception","errorClass":"IllegalArgumentException","httpStatus":null,"severity":"error","filePath":"pulsar-common/src/main/java/org/apache/pulsar/common/policies/data/OffloadPoliciesImpl.java","lineNumber":371,"sourceCode":"        return false;\n    }\n\n    public Properties toProperties() {\n        Properties properties = new Properties();\n        for (Field f : CONFIGURATION_FIELDS) {\n            try {\n                f.setAccessible(true);\n                if (\"managedLedgerExtraConfigurations\".equals(f.getName())) {\n                    @SuppressWarnings(\"unchecked\") // field type is Map<String, String>\n                    Map<String, String> extraConfig = (Map<String, String>) f.get(this);\n                    extraConfig.forEach((key, value) -> {\n                        setProperty(properties, EXTRA_CONFIG_PREFIX + key, value);\n                    });\n                } else {\n                    setProperty(properties, f.getName(), f.get(this));\n                }\n            } catch (Exception e) {\n                throw new IllegalArgumentException(\"An error occurred while processing the field: \" + f.getName(), e);\n            }\n        }\n        return properties;\n    }\n\n    private static void setProperty(Properties properties, String key, Object value) {\n        if (value != null) {\n            properties.setProperty(key, \"\" + value);\n        }\n    }\n\n    @Target(ElementType.FIELD)\n    @Retention(RetentionPolicy.RUNTIME)\n    private @interface Configuration {\n\n    }\n\n    /**","sourceCodeStart":353,"sourceCodeEnd":389,"githubUrl":"https://github.com/apache/pulsar/blob/820761864ed8e2a7d2e52dd9763ad2ae117c1395/pulsar-common/src/main/java/org/apache/pulsar/common/policies/data/OffloadPoliciesImpl.java#L353-L389","documentation":"OffloadPoliciesImpl.toProperties() reflects over every field of the offload policies object and copies it into a Properties map. If reflective access on any field throws (IllegalAccessException, unexpected getter/value problems), it is wrapped in this IllegalArgumentException naming the offending field. It indicates the policies object is in a state reflection cannot serialize, not a data-value problem.","triggerScenarios":"Calling toProperties() on an OffloadPoliciesImpl instance where a field's getter throws or is inaccessible — e.g. a subclassed/anonymized instance, a field with a throwing custom getter, or reflection restrictions (Java module system / SecurityManager) blocking f.get(this).","commonSituations":"Programmatic construction of offload policies with unusual field values, running on newer JDKs with strict module access, or frameworks wrapping the policy object in a proxy before calling config serialization.","solutions":["Identify the field named in the message and check its getter/initialization for throwing code","Construct OffloadPoliciesImpl via its builder/setters rather than subclassing or proxying it","Run on a JDK where reflective access to pulsar-common classes is permitted; add --add-opens if module access errors occur","Update to a recent Pulsar version where offload policy serialization is more robust"],"exampleFix":"// before\nOffloadPoliciesImpl policies = new OffloadPoliciesImpl() { /* anonymous subclass breaks reflection */ };\nProperties props = policies.toProperties();\n// after\nOffloadPoliciesImpl policies = OffloadPoliciesImpl.builder()\n    .bucket(\"my-bucket\").region(\"us-east-1\").build();\nProperties props = policies.toProperties();","handlingStrategy":"try-catch","validationCode":"// Ensure the instance is a plain OffloadPoliciesImpl built via builder/setters\nif (!(policies instanceof OffloadPoliciesImpl) || policies.getClass() != OffloadPoliciesImpl.class) {\n    throw new IllegalStateException(\"Use a non-proxied OffloadPoliciesImpl for toProperties()\");\n}","typeGuard":"static boolean isPlainOffloadPolicies(Object o) {\n    return o != null && o.getClass() == OffloadPoliciesImpl.class;\n}","tryCatchPattern":"try {\n    Properties props = policies.toProperties();\n} catch (IllegalArgumentException e) {\n    log.error(\"Offload policy field failed: {}\", e.getMessage(), e.getCause());\n    throw new ConfigException(\"Invalid offload policies configuration\", e);\n}","preventionTips":["Build policies via OffloadPoliciesImpl.builder()/setters, never subclass or proxy","Test toProperties() in CI for any custom policy construction path","Keep JDK module opens for org.apache.pulsar.common if using strict module settings","Log the failing field name from the exception before retrying with defaults"],"tags":["reflection","serialization","configuration"],"backgroundTag":"reflective-field-access-failed","analyzedSha":"820761864ed8e2a7d2e52dd9763ad2ae117c1395","analyzedAt":"2026-09-06T00:14:20.138Z","contentChangedAt":"2026-09-06T00:14:20.138Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}