public static GryoPool getGryoPool() {
        if (!INITIALIZED) {
            final Configuration configuration = SystemUtil.getSystemPropertiesConfiguration("tinkerpop", true);
            HadoopGraph.LOGGER.warn("The " + HadoopPools.class.getSimpleName() + " has not been initialized, using system properties configuration: " + ConfigurationUtils.toString(configuration));
            initialize(configuration);
        }
        return GRYO_POOL;
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/structure/io/HadoopPools.java