title: Spark Dataframe with JSON as String in it, to be cast as nested json
body: <p>I am having trouble processing JSON data in Spark.</p>
  
  <p>The DataFrame has a column that has JSON in String format.</p>
  
  <p>DF Schema:</p>
  
  <pre><code>root
   |-- id: string (nullable = true)
   |-- jsonString: string (nullable = true)
  </code></pre>
  
  <p>Sample jsonString:<code>"{\"sample\":\"value\"}";</code></p>
  
  <p>I want to convert this jsonString as a nested JSON object. This enables to read and traverse through the JSON data.</p>
  
  <p>Target DF structure I am looking for is as follows.</p>
  
  <pre><code>root
   |-- id: string (nullable = true)
   |-- json: struct (nullable = true)
   |   |-- sample: string (nullable = true)
  </code></pre>
  
  <p>Appreciate any help.</p>