title: append a json string to a file
body: <p>How to append a json string to a file that already contains json strings(in java)?
  I tried reading the file into memory using objectmapper and then append it and put it back into file.</p>
  
  <pre><code>ObjectMapper mapper = new ObjectMapper();
  HashMap&lt;String, Object&gt; jsonMap = mapper.readValue( new File(workflowSessionFilePath), new TypeReference&lt;HashMap&lt;String, Object&gt;&gt;() {});
  
  jsonMap.put("key", "value");
  mapper.defaultPrettyPrintingWriter().writeValue(new File(workflowSessionFilePath), jsonMap);
  </code></pre>
  
  <p>But is there a better way than this?</p>