@Override
        public void setConf(final Configuration configuration) {
            super.setConf(configuration);
            final org.apache.commons.configuration2.Configuration apacheConfiguration = ConfUtil.makeApacheConfiguration(configuration);
            this.comparator = MapReduce.<MapReduce<?,?,?,?,?>>createMapReduce(HadoopGraph.open(apacheConfiguration),apacheConfiguration).getReduceKeySort().get();
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/structure/io/ObjectWritableComparator.java