wso2 cloning from two different api - wso2

Question

I am trying to clone 2 different api to combine their response but i am always getting a null pointer error. at first i am just trying to clone these 2 api.
<?xml version="1.0" encoding="UTF-8"?>
<api context="/movieapi" name="movieapi" xmlns="http://ws.apache.org/ns/synapse">
<resource methods="GET" uri-template="/movie/{imdbId}">
<inSequence>
<property expression="get-property('uri.var.imdbId')" name="uri.var.imdbId" scope="default" type="STRING"/>
<clone>
<target>
<endpoint>
<address trace="disable" uri="https://api.themoviedb.org/3/movie/{uri.var.imdbId}?api_key=code&append_to_response=casts,images"/>
</endpoint>
</target>
<target>
<endpoint>
<address trace="disable" uri="http://www.omdbapi.com/?type=movie&i={uri.var.imdbId}"/>
</endpoint>
</target>
</clone>
</inSequence>
</resource>
</api>
Here is my error from wso2esb version 5 beta
[2016-07-15 13:57:34,106] ERROR - PassThroughHttpSender Failed to submit the response
java.lang.NullPointerException
at org.apache.synapse.transport.passthru.util.SourceResponseFactory.create(SourceResponseFactory.java:67)
at org.apache.synapse.transport.passthru.PassThroughHttpSender.submitResponse(PassThroughHttpSender.java:463)
at org.apache.synapse.transport.passthru.PassThroughHttpSender.invoke(PassThroughHttpSender.java:264)
at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:442)
at org.apache.synapse.core.axis2.Axis2Sender.sendBack(Axis2Sender.java:212)
at org.apache.synapse.rest.Resource.process(Resource.java:348)
at org.apache.synapse.rest.API.process(API.java:336)
at org.apache.synapse.rest.RESTRequestHandler.apiProcess(RESTRequestHandler.java:120)
at org.apache.synapse.rest.RESTRequestHandler.dispatchToAPI(RESTRequestHandler.java:100)
at org.apache.synapse.rest.RESTRequestHandler.process(RESTRequestHandler.java:55)
at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.injectMessage(Axis2SynapseEnvironment.java:304)
at org.apache.synapse.core.axis2.SynapseCallbackReceiver.handleMessage(SynapseCallbackReceiver.java:541)
at org.apache.synapse.core.axis2.SynapseCallbackReceiver.receive(SynapseCallbackReceiver.java:179)
at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
at org.apache.synapse.transport.passthru.ClientWorker.run(ClientWorker.java:252)
at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
[2016-07-15 13:57:34,121] ERROR - Axis2Sender Access-Control-Allow-Origin:*,Cache-Control:public, max-age=28800,Content-Type:application/json;charset=utf-8,ETag:"37a6259cc0c1dae299a7866489dff0bd",Status:404 Not Found,X-Memc:MISS,X-Memc-Age:0,X-Memc-Expires:28800,X-Memc-Key:d0c5ca8e07e81f5246e96c9e4bd54753,X-RateLimit-Limit:40,X-RateLimit-Remaining:39,X-RateLimit-Reset:1468562263,<?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope"><soapenv:Body/></soapenv:Envelope> Unexpected error sending message back
org.apache.axis2.AxisFault: Failed to submit the response
at org.apache.synapse.transport.passthru.PassThroughHttpSender.handleException(PassThroughHttpSender.java:613)
at org.apache.synapse.transport.passthru.PassThroughHttpSender.invoke(PassThroughHttpSender.java:266)
at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:442)
at org.apache.synapse.core.axis2.Axis2Sender.sendBack(Axis2Sender.java:212)
at org.apache.synapse.rest.Resource.process(Resource.java:348)
at org.apache.synapse.rest.API.process(API.java:336)
at org.apache.synapse.rest.RESTRequestHandler.apiProcess(RESTRequestHandler.java:120)
at org.apache.synapse.rest.RESTRequestHandler.dispatchToAPI(RESTRequestHandler.java:100)
at org.apache.synapse.rest.RESTRequestHandler.process(RESTRequestHandler.java:55)
at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.injectMessage(Axis2SynapseEnvironment.java:304)
at org.apache.synapse.core.axis2.SynapseCallbackReceiver.handleMessage(SynapseCallbackReceiver.java:541)
at org.apache.synapse.core.axis2.SynapseCallbackReceiver.receive(SynapseCallbackReceiver.java:179)
at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
at org.apache.synapse.transport.passthru.ClientWorker.run(ClientWorker.java:252)
at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at org.apache.synapse.transport.passthru.util.SourceResponseFactory.create(SourceResponseFactory.java:67)
at org.apache.synapse.transport.passthru.PassThroughHttpSender.submitResponse(PassThroughHttpSender.java:463)
at org.apache.synapse.transport.passthru.PassThroughHttpSender.invoke(PassThroughHttpSender.java:264)
... 16 more
[2016-07-15 13:57:34,124] INFO - LogMediator To: http://www.w3.org/2005/08/addressing/anonymous, WSAction: , SOAPAction: , MessageID: urn:uuid:f814f333-463b-4f51-89f1-2c361d7c55ae, Direction: response, MESSAGE = Executing default 'fault' sequence, ERROR_CODE = 0, ERROR_MESSAGE = Access-Control-Allow-Origin:*,Cache-Control:public, max-age=28800,Content-Type:application/json;charset=utf-8,ETag:"37a6259cc0c1dae299a7866489dff0bd",Status:404 Not Found,X-Memc:MISS,X-Memc-Age:0,X-Memc-Expires:28800,X-Memc-Key:d0c5ca8e07e81f5246e96c9e4bd54753,X-RateLimit-Limit:40,X-RateLimit-Remaining:39,X-RateLimit-Reset:1468562263,<?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope"><soapenv:Body/></soapenv:Envelope> Unexpected error sending message back, Payload: {"status_code":34,"status_message":"The resource you requested could not be found."}

Answer 1

Please check whether your property retrieve value from the property. For that use log mediator as follows;
<log level="full">
<property expression="get-property('uri.var.imdbId')" name="uri.var.imdbId" scope="default" type="STRING"/>
</log>
Then the issue is retrieving part.
Issue is about submitting response. According to your configuration, you didn't add aggregate mediator to gather responses [1]. Please add and test it.
I add sample scenario here. You just have to start 2 instances of SimpleStockQuote service [2] and publish messages to proxy via SOAPUI.
<proxy name="ScatterGatherProxy" startOnLoad="true" trace="disable" transports="https http">
<description/>
<target>
<inSequence>
<clone>
<target>
<sequence>
<send>
<endpoint name="vendorA">
<address uri="http://localhost:9001/services/SimpleStockQuoteService/"/>
</endpoint>
</send>
</sequence>
</target>
<target>
<sequence>
<send>
<endpoint name="vendorB">
<address uri="http://localhost:9002/services/SimpleStockQuoteService/"/>
</endpoint>
</send>
</sequence>
</target>
</clone>
</inSequence>
<outSequence>
<log level="full"/>
<aggregate>
<completeCondition>
<messageCount min="2"/>
</completeCondition>
<onComplete expression="//m0:return"
xmlns:m0="http://services.samples" xmlns:m1="http://services.samples/xsd">
<enrich>
<source clone="true" xpath="//m0:return[not(preceding-sibling::m0:return/m1:last <= m1:last) and not(following-sibling::m0:return/m1:last < m1:last)]"/>
<target type="body"/>
</enrich>
<send/>
</onComplete>
</aggregate>
</outSequence>
</target>
[1] https://docs.wso2.com/display/ESB490/Aggregate+Mediator
[2] https://docs.wso2.com/display/ESB490/Setting+Up+the+ESB+Samples#Starting%20the%20Axis2%20server