如何克服scala NoSuchMethodError?

问题描述

刚开始使用Scala和Spark尝试运行这个简单的程序:

just getting started with scala and sparktrying to run this simple program:

package spark.example

import org.apache.spark.SparkContext
import org.apache.spark.SparkContext._
import org.apache.spark.SparkConf

object SparkGrep {
  def main(args: Array[String] = Array("default argument")) {
    val conf = new SparkConf().setAppName("SparkGrep").setMaster("localhost")
    val sc = new SparkContext(conf)
    val inputFile = sc.textFile("/Users/eugene/Downloads/hello.txt").cache()
    val matchTerm : String = "hello"
    val numMatches = inputFile.filter(line => line.contains(matchTerm)).count()
    println("%s lines in %s contain %s".format(numMatches, args(1), matchTerm))
    System.exit(0)
  }
}

出现此错误:

Exception in thread "main" java.lang.NoSuchMethodError: scala.collection.immutable.HashSet$.empty()Lscala/collection/immutable/HashSet;
    at akka.actor.ActorCell$.<init>(ActorCell.scala:305)
    at akka.actor.ActorCell$.<clinit>(ActorCell.scala)
    at akka.actor.RootActorPath.$div(ActorPath.scala:152)
    at akka.actor.LocalActorRefProvider.<init>(ActorRefProvider.scala:465)
    at akka.remote.RemoteActorRefProvider.<init>(RemoteActorRefProvider.scala:124)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at akka.actor.ReflectiveDynamicAccess$$anonfun$createInstanceFor$2.apply(DynamicAccess.scala:78)
    at scala.util.Try$.apply(Try.scala:192)
    at akka.actor.ReflectiveDynamicAccess.createInstanceFor(DynamicAccess.scala:73)
    at akka.actor.ReflectiveDynamicAccess$$anonfun$createInstanceFor$3.apply(DynamicAccess.scala:84)
    at akka.actor.ReflectiveDynamicAccess$$anonfun$createInstanceFor$3.apply(DynamicAccess.scala:84)
    at scala.util.Success.flatMap(Try.scala:231)
    at akka.actor.ReflectiveDynamicAccess.createInstanceFor(DynamicAccess.scala:84)
    at akka.actor.ActorSystemImpl.<init>(ActorSystem.scala:550)
    at akka.actor.ActorSystem$.apply(ActorSystem.scala:111)
    at akka.actor.ActorSystem$.apply(ActorSystem.scala:104)
    at org.apache.spark.util.AkkaUtils$.createActorSystem(AkkaUtils.scala:96)
    at org.apache.spark.SparkEnv$.create(SparkEnv.scala:126)
    at org.apache.spark.SparkContext.<init>(SparkContext.scala:139)
    at spark.example.SparkGrep$.main(SparkGrep.scala:14)
    at spark.example.SparkGrep.main(SparkGrep.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)

我应该在此简单代码中进行哪些更改以使其运行?

What should I change in this simple code to make it run?

推荐答案

这是一个很常见的错误，忘记了Spark是针对旧版本的Scala(2.10.x，从Spark 1.6.1开始，即将通过Spark 2.0进行更改).

This is a rather common mistake of forgetting Spark is compiled against an older version of Scala (2.10.x, as of Spark 1.6.1 (this is subject to change soon with Spark 2.0)).

更改代码以使用所述版本进行编译应会解决您的运行时问题.

Changing your code to compile with the said version should fix you runtime issue.

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