title: NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less
body: <p>I have seen many answers related to this error, but all re-directing to scala versions etc. But I think my case is different.</p>
  
  <p>I have a remote spark master-worker cluster set up with version 2.10. I was able to verify it through <strong><a href="http://master-ip:8080" rel="noreferrer">http://master-ip:8080</a></strong> listing all worker nodes</p>
  
  <p>From my application, I am trying to create SparkConf with Java 7 code. Following below is the code</p>
  
  <pre><code>sparkConf = new SparkConf(true)
                  .set("spark.cassandra.connection.host", "localhost")
                  .set("spark.cassandra.auth.username", "username")
                  .set("spark.cassandra.auth.password", "pwd")
                  .set("spark.master", "spark://master-ip:7077")
                  .set("spark.app.name","Test App");
  </code></pre>
  
  <p>Following are the maven dependencies i added</p>
  
  <pre><code>&lt;dependency&gt;
              &lt;groupId&gt;com.datastax.spark&lt;/groupId&gt;
              &lt;artifactId&gt;spark-cassandra-connector_2.10&lt;/artifactId&gt;
              &lt;version&gt;2.0.1&lt;/version&gt;
          &lt;/dependency&gt;
          &lt;dependency&gt;
              &lt;groupId&gt;org.apache.spark&lt;/groupId&gt;
              &lt;artifactId&gt;spark-core_2.11&lt;/artifactId&gt;
              &lt;version&gt;2.1.0&lt;/version&gt;
              &lt;exclusions&gt;
                  &lt;exclusion&gt;
                      &lt;groupId&gt;javax.validation&lt;/groupId&gt;
                      &lt;artifactId&gt;validation-api&lt;/artifactId&gt;
                  &lt;/exclusion&gt;
              &lt;/exclusions&gt;
          &lt;/dependency&gt;
  </code></pre>
  
  <p>I get the below error</p>
  
  <pre><code>Caused by: java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;
      at org.apache.spark.util.Utils$.getSystemProperties(Utils.scala:1710)
      at org.apache.spark.SparkConf.loadFromSystemProperties(SparkConf.scala:73)
      at org.apache.spark.SparkConf.&lt;init&gt;(SparkConf.scala:68)
  </code></pre>
  
  <p>Spark Version from one of the worker nodes</p>
  
  <pre><code>./spark-shell --version
  Welcome to
       ____              __
      / __/__  ___ _____/ /__
     _\ \/ _ \/ _ `/ __/  '_/
    /___/ .__/\_,_/_/ /_/\_\   version 2.1.0
       /_/
  
  Using Scala version 2.11.8, Java HotSpot(TM) 64-Bit Server VM, 1.8.0_91
  Branch 
  Compiled by user jenkins on 2016-12-16T02:04:48Z
  Revision 
  Url 
  Type --help for more information.
  </code></pre>