{"record":{"id":"67f83f9c5e92fbc7","repo":"apache/hadoop","slug":"mismatched-checkpoint-type-id-getclass","errorCode":null,"errorMessage":"Mismatched checkpoint type: ${id.getClass()}","messagePattern":"Mismatched checkpoint type: (.+?)","errorType":"validation","errorClass":"IllegalArgumentException","httpStatus":null,"severity":"error","filePath":"hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/checkpoint/FSCheckpointService.java","lineNumber":105,"sourceCode":"\n    @Override\n    public void close() throws IOException {\n      isOpen=false;\n      out.close();\n    }\n\n    @Override\n    public boolean isOpen() {\n      return isOpen;\n    }\n\n  }\n\n  @Override\n  public CheckpointReadChannel open(CheckpointID id)\n      throws IOException, InterruptedException {\n      if (!(id instanceof FSCheckpointID)) {\n        throw new IllegalArgumentException(\n            \"Mismatched checkpoint type: \" + id.getClass());\n      }\n      return new FSCheckpointReadChannel(\n          fs.open(((FSCheckpointID) id).getPath()));\n  }\n\n  private static class FSCheckpointReadChannel\n      implements CheckpointReadChannel {\n\n    private boolean isOpen = true;\n    private final ReadableByteChannel in;\n\n    FSCheckpointReadChannel(FSDataInputStream in){\n      this.in = Channels.newChannel(in);\n    }\n\n    @Override\n    public int read(ByteBuffer bb) throws IOException {","sourceCodeStart":87,"sourceCodeEnd":123,"githubUrl":"https://github.com/apache/hadoop/blob/2add9630210752f88ceb1bb74eb65e37bf41da8e/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/checkpoint/FSCheckpointService.java#L87-L123","documentation":"Error \"Mismatched checkpoint type: ${id.getClass()}\" thrown in apache/hadoop.","triggerScenarios":"Thrown at hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/checkpoint/FSCheckpointService.java:105 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Use a checkpoint ID type matching the FSCheckpointService (FileSystemCheckpointID); mismatched custom ID types are rejected."],"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":"2026-08-23T01:17:44.959Z"}