http outbound gateway PUT request 400 Bad Request [No Body] - spring-boot

Question

<int:chain id="re-t-ob-chain" input-channel="testIntmChannel" output-channel="outputChannel">
<int:service-activator ref="testTransformer" method="preprocessRequest"/>
int:header-enricher
<int:header name="Content-Type" value="application/xml"/>
<int:header name="Accept" value="application/json"/>
</int:header-enricher>
<int-http:outbound-gateway
id="testOutboundGateway"
url-expression="headers.testUrl"
http-method="PUT"
request-factory="testRequestFactory"
extract-request-payload="true"
charset="UTF-8"
mapped-request-headers="Content-Type,Accept"
expected-response-type="com.test.integration.TestResponse">
</int-http:outbound-gateway>
</int:chain>
getting 400 Bad Request[No Body] for PUT http request call, payload is not getting passed to outbound gateway even though I see message.payload has expected request object in preprocessRequest. Request payload is in xml format.
<bean id="testRequestFactory" class="org.springframework.http.client.SimpleClientHttpRequestFactory">
<property name="connectTimeout" value="10000"/>
<property name="readTimeout" value="10000"/>
</bean>
<int-http:inbound-gateway
request-channel="rTRequestChannel"
reply-channel="rTReplyChannel"
supported-methods="PUT"
path="/test/activities"
mapped-request-headers="*"
request-payload-type="com.test.integration.request. SampleRequest">
</int-http:inbound-gateway>
Request class:
#XmlType(name="users")
#XmlRootElement(name = "users")
public class SampleRequest implements Serializable{
private List<User> users;
#XmlElement(required=true, nillable=true, name="User")
public List<User> getUsers() {
return users;
}
public void setUsers(List<User> users) {
this.users = users;
}
public SampleRequest(){
}
}
Could anyone please help?