Failed to append to HDFS
Finally got rid of the error. Apparently it is mandatory to close the FSDataOutputStream that is returned when you call create from filesystem.
That being said, this is how the method createFileInCluster from HDFSFileUtilImpl is implemented now:
@Override public void createFileInCluster(String uriOfFile) throws IOException { Validate.notEmpty(uriOfFile); FSDataOutputStream out = fileSystem.create(new Path(uriOfFile)); out.close(); }