官网链接:https://spark.apache.org
Spark runs on Java 8, Python 2.7+/3.4+ and R 3.1+. For the Scala API,
Spark 2.4.5 uses Scala 2.12. You will need to use a compatible Scala
version (2.12.x).
Exception in thread "main" java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;
at org.apache.spark.util.Utils$.getSystemProperties(Utils.scala:1767)
at org.apache.spark.SparkConf.loadFromSystemProperties(SparkConf.scala:76)
at org.apache.spark.SparkConf.<init>(SparkConf.scala:71)
at org.apache.spark.SparkConf.<init>(SparkConf.scala:58)
at ScalaSparkContext.getSparkContext(Test.scala:8)
at ScalaSparkContext.<init>(Test.scala:6)
at Test$.main(Test.scala:25)
at Test.main(Test.scala)