public static SparkContext create(org.apache.hadoop.conf.Configuration hadoopConfiguration) {
        final SparkConf sparkConfiguration = new SparkConf();
        hadoopConfiguration.forEach(entry -> sparkConfiguration.set(entry.getKey(), entry.getValue()));
        return Spark.create(sparkConfiguration);
    }
This is a static cache the prevents Spark from garbage collecting unreferenced RDDs.

@author Marko A. Rodriguez (http://markorodriguez.com)
spark-gremlin/src/main/java/org/apache/tinkerpop/gremlin/spark/structure/Spark.java