title: How to convert HashMap to JSON in Kotlin
body: <p>I have HashMap in Kotlin</p>
  
  <pre><code>val map = HashMap&lt;String, String&gt;()
  map.put("key1","value1");
  map.put("key2","value2");
  map.put("key3","value3");
  </code></pre>
  
  <p>How to convert it into String in JSON format? like</p>
  
  <pre><code>{"key1": "value1", "key2": "value2", "key3": "value3"}
  </code></pre>