title: I want to add one key and value pair in existing json file
body: <p>I want to add the key value pair like</p>
  
  <pre><code>"Signature":64237402i242840805749670 in the existing json field properties
  
  {
  "headers":{
      "JMSCorrelationID":"The JMS correlation ID",
      "JMSDeliveryMode":"The JMS delivery mode",
  
  },
  "properties":{
      "asu_timestamp":"12345678",
      "asu_type":"Ack",
  }
  </code></pre>
  
  <p>Please tell me how can I add it into Properties by using java.</p>