I am getting error while sending email with customized subject with expression :

and getting below error :

while writing Java at 
3| {"DataGenerated" : (now()) as String { format: "dd MMM KK:mm a" } }
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^.

3| {"DataGenerated" : (now()) as String { format: "dd MMM KK:mm a" } }
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Trace:
  at anonymous::main (line: 3, column: 20)" evaluating expression: "output application/json
---
{"DataGenerated" : (now()) as String { format: "dd MMM KK:mm a" } }".
Element               : mongodbconnectFlow/processors/1 @ datagenerator-api:datagenerator-api.xml:36
Element DSL           : <email:send doc:id="e89769cc-f214-44a7-a772-d4a6f626aada" config-ref="Email_SMTP" fromAddress="[email protected]" subject="#[output application/json
---
{"DataGenerated" : (now()) as String { format: "dd MMM KK:mm a" } }]">

I want to get the subject as "DataGenerated": "07 Aug 01:43 PM"