title: How to check if a process definition key exist in camunda using services?
body: <p>I am trying to know if a process definition key exists in Camunda using its services.</p>
  <p>I am aware of the rest api to fetch the details which is - GET /process-definition/key/{key}.</p>
  <p>But instead of using rest calls, I would like to use the service's methods to achieve in my Java code.</p>