REST Api Error

[alex_drinkwater]

I think this got introduced in 5.16.1.

GET runtime/process-instances/{processInstanceId}/variables

When I call this api endpoint with a valid process instance id I get a 500.

HTTP Status 500 - An exception occured writing the response entity

Can anyone else reproduce this?

[jbarrez]

Shouldn't be, we've got unit tests for that call: https://github.com/Activiti/Activiti/blob/master/modules/activiti-rest/src/test/java/org/activiti/re...

Is that all you get in the log? No stack trace?

[alex_drinkwater]

Oct 17, 2014 9:10:06 AM org.restlet.engine.adapter.ServerAdapter commit
Here is the stack trace:

SEVERE: An exception occured writing the response entity
java.io.IOException: javax.xml.stream.XMLStreamException: Trying to output second root, <ArrayList>
at com.fasterxml.jackson.dataformat.xml.util.StaxUtil.throwXmlAsIOException(StaxUtil.java:24)
at com.fasterxml.jackson.dataformat.xml.ser.ToXmlGenerator._handleStartObject(ToXmlGenerator.java:428)
at com.fasterxml.jackson.dataformat.xml.ser.ToXmlGenerator.writeStartObject(ToXmlGenerator.java:397)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:138)
at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:100)
at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:21)
at com.fasterxml.jackson.databind.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:186)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:222)
at com.fasterxml.jackson.dataformat.xml.ser.XmlSerializerProvider.serializeValue(XmlSerializerProvider.java:87)
at com.fasterxml.jackson.databind.ObjectWriter._configAndWriteValue(ObjectWriter.java:683)
at com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:534)
at org.restlet.ext.jackson.JacksonRepresentation.write(JacksonRepresentation.java:474)
at org.restlet.engine.adapter.ServerCall.writeResponseBody(ServerCall.java:519)
at org.restlet.engine.adapter.ServerCall.sendResponse(ServerCall.java:463)
at org.restlet.ext.servlet.internal.ServletCall.sendResponse(ServletCall.java:430)
at org.restlet.engine.adapter.ServerAdapter.commit(ServerAdapter.java:196)
at org.restlet.engine.adapter.HttpServerHelper.handle(HttpServerHelper.java:153)
at org.restlet.ext.servlet.ServerServlet.service(ServerServlet.java:1118)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
Caused by: javax.xml.stream.XMLStreamException: Trying to output second root, <ArrayList>
at com.ctc.wstx.sw.BaseStreamWriter.throwOutputError(BaseStreamWriter.java:1522)
at com.ctc.wstx.sw.BaseStreamWriter.throwOutputError(BaseStreamWriter.java:1529)
at com.ctc.wstx.sw.BaseStreamWriter.reportNwfStructure(BaseStreamWriter.java:1557)
at com.ctc.wstx.sw.BaseNsStreamWriter.checkStartElement(BaseNsStreamWriter.java:469)
at com.ctc.wstx.sw.RepairingNsStreamWriter.writeStartOrEmpty(RepairingNsStreamWriter.java:255)
at com.ctc.wstx.sw.BaseNsStreamWriter.writeStartElement(BaseNsStreamWriter.java:310)
at com.fasterxml.jackson.dataformat.xml.ser.ToXmlGenerator._handleStartObject(ToXmlGenerator.java:426)
… 33 more

[jbarrez]

Do you have some XML serializer (JAXP/JAXB or whatever) on your classpath? The error seems to point in that direction