How to create custom template for service task?


#1

we have created below template for service task , How can we create simple custom template that sends email using service task in modeler. we are not able to deploy workflow to camunda engine. below here is the error

  {
      "name": "Mail Task",
      "id": "com.camunda.example.MailTask",
      "createdBy": "sh529u",
      "users": [],
      "groups": [],
      "properties": [
    {
      "binding": {
        "name": "camunda:javaDelegate",
        "type": "property"
      },
      "editable": false,
      "value": "com.mycompany.MailTaskImpl",
      "type": "String",
      "label": "Implementation Type"
    },
    {
      "constraints": {
        "notEmpty": true
      },
      "binding": {
        "scriptFormat": "freemarker",
        "name": "messageBody",
        "type": "camunda:inputParameter"
      },
      "type": "Text",
      "value": "Hello ${firstName}!",
      "description": "You can use freemarker templates ${...} here",
      "label": "Template"
    },
    {
      "binding": {
        "source": "${ resultStatus }",
        "type": "camunda:outputParameter"
      },
      "value": "mailSendResult",
      "type": "String",
      "description": "Process variable to assign the send result to",
      "label": "Result Status"
    },
    {
      "binding": {
        "name": "camunda:asyncBefore",
        "type": "property"
      },
      "value": true,
      "type": "Boolean",
      "label": "Send Async?"
    }
      ],
      "appliesTo": [
    "bpmn:ServiceTask"
      ]
    }

ERROR

03-Jul-2017 10:31:27.047 WARNING [http-nio-8651-exec-1] null.null org.camunda.bpm.engine.ProcessEngineException: ENGINE-09005 Could not parse BPMN process. Errors:
* One of the attributes 'class', 'delegateExpression', 'type', or 'expression' is mandatory on serviceTask. | diagram.bpmn | line 2 | column 961