title: Warnings while building Scala/Spark project with SBT
body: <p>I'm trying to build a Scala/Spark project in IntelliJ Idea with the following <code>build.sbt</code>:</p>
  
  <pre><code>name := "try"
  
  version := "1.0"
  
  scalaVersion := "2.11.8"
  
  val sparkVersion = "2.2.0"
  
  resolvers ++= Seq(
    "apache-snapshots" at "http://repository.apache.org/snapshots/"
  )
  
  libraryDependencies ++= Seq(
    "org.apache.spark" %% "spark-core" % sparkVersion,
    "org.apache.spark" %% "spark-sql" % sparkVersion,
    "org.apache.spark" %% "spark-mllib" % sparkVersion,
    "org.apache.spark" %% "spark-streaming" % sparkVersion,
    "org.apache.spark" %% "spark-hive" % sparkVersion
  )
  </code></pre>
  
  <p>and getting a bunch of warnings:</p>
  
  <pre><code>8/6/17
  1:29 PM SBT project import
                  [warn] Found version conflict(s) in library dependencies; some are suspected to be binary incompatible:
                  [warn]  * io.netty:netty:3.9.9.Final is selected over {3.6.2.Final, 3.7.0.Final}
                  [warn]      +- org.apache.spark:spark-core_2.11:2.2.0             (depends on 3.9.9.Final)
                  [warn]      +- org.apache.zookeeper:zookeeper:3.4.6               (depends on 3.6.2.Final)
                  [warn]      +- org.apache.hadoop:hadoop-hdfs:2.6.5                (depends on 3.6.2.Final)
                  [warn]  * commons-net:commons-net:2.2 is selected over 3.1
                  [warn]      +- org.apache.spark:spark-core_2.11:2.2.0             (depends on 2.2)
                  [warn]      +- org.apache.hadoop:hadoop-common:2.6.5              (depends on 3.1)
                  [warn]  * com.google.guava:guava:11.0.2 is selected over {12.0.1, 16.0.1}
                  [warn]      +- org.apache.hadoop:hadoop-yarn-client:2.6.5         (depends on 11.0.2)
                  [warn]      +- org.apache.hadoop:hadoop-yarn-api:2.6.5            (depends on 11.0.2)
                  [warn]      +- org.apache.hadoop:hadoop-yarn-common:2.6.5 
  </code></pre>
  
  <p>I have several, perhaps dumb, questions:</p>
  
  <ol>
  <li>Is there a better way to structure <code>build.sbt</code> (add other resolvers e.g.?), so that I can get rid off the warnings?</li>
  <li>Should I care about warnings at all?</li>
  </ol>