{"record":{"id":"c74f0d6aa5bfdc87","repo":"eclipse-vertx/vert.x","slug":"unknown-resolvedaddresstypes-resolvedaddresstype","errorCode":null,"errorMessage":"Unknown ResolvedAddressTypes ${resolvedAddressTypes}","messagePattern":"Unknown ResolvedAddressTypes (.+?)","errorType":"exception","errorClass":"java.lang.IllegalArgumentException","httpStatus":null,"severity":"error","filePath":"vertx-core/src/main/java/io/vertx/core/dns/impl/DnsAddressResolverProvider.java","lineNumber":174,"sourceCode":"    if (address == null) {\n      address = lookup(inetHost.toLowerCase(Locale.ENGLISH), resolvedAddressTypes);\n    }\n    return address;\n  }\n  InetAddress lookup(String inetHost, ResolvedAddressTypes resolvedAddressTypes) {\n    switch (resolvedAddressTypes) {\n      case IPV4_ONLY:\n        return parsedHostsFile.inet4Entries().get(inetHost);\n      case IPV6_ONLY:\n        return parsedHostsFile.inet6Entries().get(inetHost);\n      case IPV4_PREFERRED:\n        Inet4Address inet4Address = parsedHostsFile.inet4Entries().get(inetHost);\n        return inet4Address != null? inet4Address : parsedHostsFile.inet6Entries().get(inetHost);\n      case IPV6_PREFERRED:\n        Inet6Address inet6Address = parsedHostsFile.inet6Entries().get(inetHost);\n        return inet6Address != null? inet6Address : parsedHostsFile.inet4Entries().get(inetHost);\n      default:\n        throw new IllegalArgumentException(\"Unknown ResolvedAddressTypes \" + resolvedAddressTypes);\n    }\n  }\n\n  public DnsNameResolverBuilder getDnsNameResolverBuilder() {\n    return dnsNameResolverBuilder;\n  }\n\n  /**\n   * @return a list of DNS servers available to use\n   */\n  public List<InetSocketAddress> nameServerAddresses() {\n    return serverList;\n  }\n\n  @Override\n  public AddressResolverGroup<InetSocketAddress> resolver(AddressResolverOptions options) {\n    return resolverGroup;\n  }","sourceCodeStart":156,"sourceCodeEnd":192,"githubUrl":"https://github.com/eclipse-vertx/vert.x/blob/fb308bd8c3f12c79f4ae89bef67fadf6c80d036e/vertx-core/src/main/java/io/vertx/core/dns/impl/DnsAddressResolverProvider.java#L156-L192","documentation":"Defensive guard in the hosts-file lookup path: the ResolvedAddressTypes enum did not match any of the known cases (IPV4_ONLY, IPV6_ONLY, IPV4_PREFERRED, IPV6_PREFERRED) in the switch. This indicates a new/unexpected enum constant or a corrupted value rather than a user input error.","triggerScenarios":"Thrown at vertx-core/src/main/java/io/vertx/core/dns/impl/DnsAddressResolverProvider.java:174 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Ensure the AddressResolverOptions resolving back to a supported ResolvedAddressTypes value","Upgrade Vert.x so the enum and this switch agree if a new address type was introduced"],"exampleFix":null,"handlingStrategy":"type-guard","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"fb308bd8c3f12c79f4ae89bef67fadf6c80d036e","analyzedAt":"2026-09-06T11:37:12.241Z","contentChangedAt":"2026-09-06T11:37:12.241Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}