在使用spark sql時一直運行報這個錯誤，最后仔細排查竟然是引入了兩個scala library 。去除其中一個scala的編譯器即可
Exception in thread "main" java.lang.NoClassDefFoundError: scala/Product$class
at org.apache.spark.SparkConf$DeprecatedConfig.<init>(SparkConf.scala:781)
at org.apache.spark.SparkConf$.<init>(SparkConf.scala:632)
at org.apache.spark.SparkConf$.<clinit>(SparkConf.scala)
at org.apache.spark.SparkConf.set(SparkConf.scala:92)
at org.apache.spark.SparkConf.set(SparkConf.scala:81)
at org.apache.spark.SparkConf.setAppName(SparkConf.scala:118)
at com.hand.study.SparkStudy$.main(SparkStudy.scala:15)
at com.hand.study.SparkStudy.main(SparkStudy.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
Caused by: java.lang.ClassNotFoundException: scala.Product$class
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 13 more
Process finished with exit code 1