{"record":{"id":"0fe6e31d82d662ed","repo":"apache/hadoop","slug":"duplicate-mapping","errorCode":null,"errorMessage":"Duplicate mapping: {} {} {}","messagePattern":"Duplicate mapping: (.+?) (.+?) (.+?)","errorType":"exception","errorClass":"IllegalStateException","httpStatus":null,"severity":"error","filePath":"hadoop-tools/hadoop-fs2img/src/main/java/org/apache/hadoop/hdfs/server/namenode/UGIResolver.java","lineNumber":89,"sourceCode":"  private final Map<String, Integer> users;\n  private final Map<String, Integer> groups;\n\n  public UGIResolver() {\n    this(new HashMap<String, Integer>(), new HashMap<String, Integer>());\n  }\n\n  UGIResolver(Map<String, Integer> users, Map<String, Integer> groups) {\n    this.users = users;\n    this.groups = groups;\n  }\n\n  public Map<Integer, String> ugiMap() {\n    Map<Integer, String> ret = new HashMap<>();\n    for (Map<String, Integer> m : Arrays.asList(users, groups)) {\n      for (Map.Entry<String, Integer> e : m.entrySet()) {\n        String s = ret.put(e.getValue(), e.getKey());\n        if (s != null) {\n          throw new IllegalStateException(\"Duplicate mapping: \" +\n              e.getValue() + \" \" + s + \" \" + e.getKey());\n        }\n      }\n    }\n    return ret;\n  }\n\n  public abstract void addUser(String name);\n\n  protected void addUser(String name, int id) {\n    Integer uid = users.put(name, id);\n    if (uid != null) {\n      throw new IllegalArgumentException(\"Duplicate mapping: \" + name +\n          \" \" + uid + \" \" + id);\n    }\n  }\n\n  public abstract void addGroup(String name);","sourceCodeStart":71,"sourceCodeEnd":107,"githubUrl":"https://github.com/apache/hadoop/blob/2add9630210752f88ceb1bb74eb65e37bf41da8e/hadoop-tools/hadoop-fs2img/src/main/java/org/apache/hadoop/hdfs/server/namenode/UGIResolver.java#L71-L107","documentation":"Error \"Duplicate mapping: {} {} {}\" thrown in apache/hadoop.","triggerScenarios":"Two different user or group names map to the same numeric id in UGIResolver, so the fsimage would contain an ambiguous mapping; the input mapping data is inconsistent.","commonSituations":"See trigger scenarios.","solutions":["Remove the duplicate user/group mapping entry from the UGI mapping input so each name maps once."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"2add9630210752f88ceb1bb74eb65e37bf41da8e","analyzedAt":"2026-08-22T19:55:07.957Z","schemaVersion":2},"datasetVersion":"2026-08-22T20:17:22.307Z"}