Kendre Paresh Kendre Paresh - 11 months ago 72
reST (reStructuredText) Question

Mule - java.lang.String cannot be cast to java.util.Map

I want to write a mule application which will read the database for unprocessed records, club them in JSON payload format and then hit a REST webservice.
I am able to read the records from the database and able to convert the database records in JSON. However, whenever I run the application I am getting following exception

java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Map

Here is my Mule configuration XML

<?xml version="1.0" encoding="UTF-8"?>

<mule xmlns:db="" xmlns:json="" xmlns:http="" xmlns="" xmlns:doc=""
<db:mysql-config name="MySQL_Configuration" host="localhost" port="3306" user="root" database="my_database_name" doc:name="MySQL Configuration"/>
<http:request-config name="HTTP_Request_Configuration" protocol="HTTPS" host="" port="8000" basePath="API" doc:name="HTTP Request Configuration"/>
<flow name="cwg_clientFlow">
<poll doc:name="Poll">
<db:select config-ref="MySQL_Configuration" doc:name="Database">
<db:parameterized-query><![CDATA[SELECT * FROM cwg_ws_data WHERE SyncFlag = 0]]></db:parameterized-query>
<logger message="#[payload]" level="INFO" doc:name="Logger"/>
<json:object-to-json-transformer doc:name="Object to JSON" />
<logger message="JSON Payload is #[payload]" level="INFO" doc:name="Logger"/>
<http:request config-ref="HTTP_Request_Configuration" path="/cwg" method="POST" doc:name="HTTP">
<http:query-params expression="#[payload]"/>
<http:header headerName="access_token" value="MQTgpMUmyQLt134maB6vPp6oWFgMtGsqzIlpCN74"/>
<logger message="webservice response #[payload]" level="INFO" doc:name="Logger"/>

I am unable to understand where it is going wrong

Please help me, I am trying this since last 2 days.

Thanks in advance

-Paresh (

Answer Source

Try removing this line.

<http:query-params expression="#[payload]"/>

It should work. As your payload is Json String and you are trying to map it to Query params which expects Map. Also for POST your payload will converted to body.