title: Spark Row created with Java ArrayList does not contain Schema
body: <p>I am trying to create Row (org.apache.spark.sql.Row) from ArrayList.</p>
  <p>here's my code</p>
  <pre><code>Row newRow = RowFactory.create(listRow.toArray());
  StructType schema = newRow.schema();
  </code></pre>
  <p>I see that schema is <em>null</em></p>
  <p>I need schema in the later part of the code to fetch fields.
  How can I create schema? if it's not getting generated automatically</p>
  <p><em>listRow is ArrayList and it contains WrappedArray()</em></p>