title: NIFI Jolt JSON date transformation not working
body: <p>In an Apache NIFI dataflow I try to transform a date from MM-dd-yyyy to yyyy-MM-dd (the default format which wil be accepted by MySQL as a date).</p>
  <p>In the NIFI advanced editor of a JoltTransformJSON 1.15.0 Processor with DSL &quot;Chain&quot; I have entered:</p>
  <p>Input Json:</p>
  <pre class="lang-json prettyprint-override"><code>{
    &quot;Name&quot;: &quot;Jan&quot;,
    &quot;Birthday&quot;: &quot;12-31-1994&quot;
  }
  </code></pre>
  <p>Transformation Jolt script:</p>
  <pre class="lang-json prettyprint-override"><code>[{
      &quot;operation&quot;: &quot;modify-overwrite-beta&quot;,
      &quot;spec&quot;: {
          &quot;Birthday&quot;: &quot;=${Birthday:toDate('MM-dd-yyyy'):format('yyyy-MM-dd')}&quot;
      }
  }]
  </code></pre>
  <p>Result:</p>
  <pre class="lang-json prettyprint-override"><code>{
    &quot;Name&quot;: &quot;Jan&quot;,
    &quot;Birthday&quot;: &quot;12-31-1994&quot;
  }
  </code></pre>
  <p>I do not get any syntax errors. It seems the Jolt transformation does not change anything.
  Why is Birthday not transformed?</p>
  <p><a href="https://i.stack.imgur.com/jKDGz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jKDGz.png" alt="enter image description here" /></a></p>