{"record":{"id":"1e8140ac7a404d47","repo":"apache/hadoop","slug":"this-stream-does-not-support-setting-the-drop-behi-1e8140","errorCode":null,"errorMessage":"this stream does not support setting the drop-behind caching setting.","messagePattern":"this stream does not support setting the drop-behind caching setting\\.","errorType":"exception","errorClass":"UnsupportedOperationException","httpStatus":null,"severity":"error","filePath":"hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FSDataInputStream.java","lineNumber":192,"sourceCode":"\n  @Override\n  public void setReadahead(Long readahead)\n      throws IOException, UnsupportedOperationException {\n    try {\n      ((CanSetReadahead)in).setReadahead(readahead);\n    } catch (ClassCastException e) {\n      throw new UnsupportedOperationException(in.getClass().getCanonicalName() +\n          \" does not support setting the readahead caching strategy.\");\n    }\n  }\n\n  @Override\n  public void setDropBehind(Boolean dropBehind)\n      throws IOException, UnsupportedOperationException {\n    try {\n      ((CanSetDropBehind)in).setDropBehind(dropBehind);\n    } catch (ClassCastException e) {\n      throw new UnsupportedOperationException(\"this stream does not \" +\n          \"support setting the drop-behind caching setting.\");\n    }\n  }\n\n  @Override\n  public ByteBuffer read(ByteBufferPool bufferPool, int maxLength,\n      EnumSet<ReadOption> opts) \n          throws IOException, UnsupportedOperationException {\n    try {\n      return ((HasEnhancedByteBufferAccess)in).read(bufferPool,\n          maxLength, opts);\n    }\n    catch (ClassCastException e) {\n      ByteBuffer buffer = ByteBufferUtil.\n          fallbackRead(this, bufferPool, maxLength);\n      if (buffer != null) {\n        extendedReadBuffers.put(buffer, bufferPool);\n      }","sourceCodeStart":174,"sourceCodeEnd":210,"githubUrl":"https://github.com/apache/hadoop/blob/2add9630210752f88ceb1bb74eb65e37bf41da8e/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FSDataInputStream.java#L174-L210","documentation":"Error \"this stream does not support setting the drop-behind caching setting.\" thrown in apache/hadoop.","triggerScenarios":"Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FSDataInputStream.java:192 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Check stream capabilities before calling setDropBehind.","Use a stream implementation that supports drop-behind caching, or omit the setting."],"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"}