Program: 5775
Project: 5775
Buggy source:
@Override public CloseableIterator<LogEvent> getLog(LoggingContext loggingContext,final long fromTimeMs,final long toTimeMs,Filter filter){
  try {
    final Filter logFilter=new AndFilter(ImmutableList.of(LoggingContextHelper.createFilter(loggingContext),filter));
    LOG.trace("String_Node_Str",fromTimeMs,toTimeMs);
    NavigableMap<Long,Location> sortedFiles=fileMetaDataManager.listFiles(loggingContext);
    if (sortedFiles.isEmpty()) {
      return null;
    }
    List<Location> filesInRange=getFilesInRange(sortedFiles,fromTimeMs,toTimeMs);
    final AvroFileReader avroFileReader=new AvroFileReader(schema);
    final Iterator<Location> filesIter=filesInRange.iterator();
    final NamespaceId namespaceId=LoggingContextHelper.getNamespaceId(loggingContext);
    CloseableIterator closeableIterator=new CloseableIterator(){
      private CloseableIterator<LogEvent> curr=null;
      @Override public void close(){
        if (curr != null) {
          curr.close();
        }
      }
      @Override public boolean hasNext(){
        return filesIter.hasNext();
      }
      @Override public CloseableIterator<LogEvent> next(){
        if (curr != null) {
          curr.close();
        }
        Location file=filesIter.next();
        LOG.trace("String_Node_Str",file);
        curr=avroFileReader.readLog(file,logFilter,fromTimeMs,toTimeMs,Integer.MAX_VALUE,namespaceId,impersonator);
        return curr;
      }
      @Override public void remove(){
        throw new UnsupportedOperationException("String_Node_Str");
      }
    }
;
    return concat(closeableIterator);
  }
 catch (  Throwable e) {
    LOG.error("String_Node_Str",e);
    throw Throwables.propagate(e);
  }
}

Fixed version (ground truth):
@Override public CloseableIterator<LogEvent> getLog(LoggingContext loggingContext,final long fromTimeMs,final long toTimeMs,Filter filter){
  try {
    final Filter logFilter=new AndFilter(ImmutableList.of(LoggingContextHelper.createFilter(loggingContext),filter));
    LOG.trace("String_Node_Str",fromTimeMs,toTimeMs);
    NavigableMap<Long,Location> sortedFiles=fileMetaDataManager.listFiles(loggingContext);
    if (sortedFiles.isEmpty()) {
      return new AbstractCloseableIterator<LogEvent>(){
        @Override protected LogEvent computeNext(){
          endOfData();
          return null;
        }
        @Override public void close(){
        }
      }
;
    }
    List<Location> filesInRange=getFilesInRange(sortedFiles,fromTimeMs,toTimeMs);
    final AvroFileReader avroFileReader=new AvroFileReader(schema);
    final Iterator<Location> filesIter=filesInRange.iterator();
    final NamespaceId namespaceId=LoggingContextHelper.getNamespaceId(loggingContext);
    CloseableIterator closeableIterator=new CloseableIterator(){
      private CloseableIterator<LogEvent> curr=null;
      @Override public void close(){
        if (curr != null) {
          curr.close();
        }
      }
      @Override public boolean hasNext(){
        return filesIter.hasNext();
      }
      @Override public CloseableIterator<LogEvent> next(){
        if (curr != null) {
          curr.close();
        }
        Location file=filesIter.next();
        LOG.trace("String_Node_Str",file);
        curr=avroFileReader.readLog(file,logFilter,fromTimeMs,toTimeMs,Integer.MAX_VALUE,namespaceId,impersonator);
        return curr;
      }
      @Override public void remove(){
        throw new UnsupportedOperationException("String_Node_Str");
      }
    }
;
    return concat(closeableIterator);
  }
 catch (  Throwable e) {
    LOG.error("String_Node_Str",e);
    throw Throwables.propagate(e);
  }
}