Only one SparkContext may be running in this JVM - [SPARK]

Question

I'm trying to run the following code to get twitter information live:

import org.apache.spark._
import org.apache.spark.streaming._
import org.apache.spark.streaming.twitter._
import org.apache.spark.streaming.StreamingContext._
import twitter4j.auth.Authorization
import twitter4j.Status
import twitter4j.auth.AuthorizationFactory
import twitter4j.conf.ConfigurationBuilder
import org.apache.spark.streaming.api.java.JavaStreamingContext

import org.apache.spark.rdd.RDD
import org.apache.spark.SparkContext
import org.apache.spark.mllib.feature.HashingTF
import org.apache.spark.mllib.linalg.Vector
import org.apache.spark.SparkConf
import org.apache.spark.api.java.JavaSparkContext
import org.apache.spark.api.java.function.Function
import org.apache.spark.streaming.Duration
import org.apache.spark.streaming.api.java.JavaDStream
import org.apache.spark.streaming.api.java.JavaReceiverInputDStream

val consumerKey = "xxx"
val consumerSecret = "xxx"
val accessToken = "xxx"
val accessTokenSecret = "xxx"
val url = "https://stream.twitter.com/1.1/statuses/filter.json"

val sparkConf = new SparkConf().setAppName("Twitter Streaming")
val sc = new SparkContext(sparkConf)

val documents: RDD[Seq[String]] = sc.textFile("").map(_.split(" ").toSeq)


// Twitter Streaming
val ssc = new JavaStreamingContext(sc,Seconds(2))

val conf = new ConfigurationBuilder()
conf.setOAuthAccessToken(accessToken)
conf.setOAuthAccessTokenSecret(accessTokenSecret)
conf.setOAuthConsumerKey(consumerKey)
conf.setOAuthConsumerSecret(consumerSecret)
conf.setStreamBaseURL(url)
conf.setSiteStreamBaseURL(url)

val filter = Array("Twitter", "Hadoop", "Big Data")

val auth = AuthorizationFactory.getInstance(conf.build())
val tweets : JavaReceiverInputDStream[twitter4j.Status] = TwitterUtils.createStream(ssc, auth, filter)

val statuses = tweets.dstream.map(status => status.getText)
statuses.print()
ssc.start()

But when it arrives at this command: val sc = new SparkContext(sparkConf), the following error appears:

17/05/09 09:08:35 WARN SparkContext: Multiple running SparkContexts detected in the same JVM! org.apache.spark.SparkException: Only one SparkContext may be running in this JVM (see SPARK-2243). To ignore this error, set spark.driver.allowMultipleContexts = true.

I have tried to add the following parameters to the sparkConf value, but the error still appears:

val sparkConf = new SparkConf().setAppName("Twitter Streaming").setMaster("local[4]").set("spark.driver.allowMultipleContexts", "true")

If I ignore the error and continue running commands I get this other error:

17/05/09 09:15:44 WARN ReceiverSupervisorImpl: Restarting receiver with delay 2000 ms: Error receiving tweets 401:Authentication credentials (https://dev.twitter.com/pages/auth) were missing or incorrect. Ensure that you have set valid consumer key/secret, access token/secret, and the system clock is in sync. \n\n\nError 401 Unauthorized HTTP ERROR: 401

Problem accessing '/1.1/statuses/filter.json'. Reason:Unauthorized

Any kind of contribution is appreciated. A greeting and have a good day.

Answer 1

A Spark-shell already prepares a spark-session or spark-context for you to use - so you don't have to / can't initialize a new one. Usually you will have a line telling you under what variable it is available to you a the end of the spark-shell launch process. allowMultipleContexts exists only for testing some functionalities of Spark, and shouldn't be used in most cases.