How do I run a local Spark 2.x Session?
<p>For testing purposes I want to have Spark 2.x run in a local mode. How can I do this? Can I do this? Currently I write in a <code>main</code>:</p>

<pre><code>val spark = SparkSession
  .builder
  .appName("RandomForestClassifierExample")
  .getOrCreate()
</code></pre>

<p>and run the main in IntelliJ, but I get the error</p>

<pre><code>org.apache.spark.SparkException: A master URL must be set in your configuration
</code></pre>

<p>I guess I need to have some local instance running or set a local mode or something like that. What should I do exactly?</p>