Use JDK8 in Travis (#834)
Use JDK8 in Travis (#834)


maasg/spark-notebook,maasg/spark-notebook,andypetrella/spark-notebook,maasg/spark-notebook,maasg/spark-notebook,spark-notebook/spark-notebook,spark-notebook/spark-notebook,andypetrella/spark-notebook,andypetrella/spark-notebook,spark-notebook/spark-notebook,spark-notebook/spark-notebook,andypetrella/spark-notebook