Camunda Rest engine embedded inside a spring app

Hi,
I need to embed camunda-rest-engine with my spring based web-app that has embedded process engine already up & running.

I have followed all instructions mentioned at https://github.com/camunda/camunda-bpm-examples/tree/master/deployment/embedded-spring-rest.

I am using Tomcat & my application starts fine however when I access http://localhost:8080/WMSProcessModelingApp/engine/default/process-definition , I get below mentioned error (Name of my war file is WMSProcessModelingApp.war)

exception

org.jboss.resteasy.spi.UnhandledException: java.lang.NullPointerException
org.jboss.resteasy.core.ExceptionHandler.handleApplicationException(ExceptionHandler.java:76)
org.jboss.resteasy.core.ExceptionHandler.handleException(ExceptionHandler.java:212)
org.jboss.resteasy.core.SynchronousDispatcher.writeException(SynchronousDispatcher.java:149)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:372)
org.jboss.resteasy.core.SynchronousDispatcher.invokePropagateNotFound(SynchronousDispatcher.java:217)
org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:224)
org.jboss.resteasy.plugins.server.servlet.FilterDispatcher.doFilter(FilterDispatcher.java:62)
org.camunda.bpm.engine.rest.filter.CacheControlFilter.doFilter(CacheControlFilter.java:41)
root cause

java.lang.NullPointerException
org.camunda.bpm.engine.rest.util.ProvidersUtil.resolveFromContext(ProvidersUtil.java:36)
org.camunda.bpm.engine.rest.impl.AbstractProcessEngineRestServiceImpl.getObjectMapper(AbstractProcessEngineRestServiceImpl.java:245)
org.camunda.bpm.engine.rest.impl.AbstractProcessEngineRestServiceImpl.getProcessDefinitionService(AbstractProcessEngineRestServiceImpl.java:68)
org.camunda.bpm.engine.rest.impl.NamedProcessEngineRestServiceImpl.getProcessDefinitionService(NamedProcessEngineRestServiceImpl.java:67)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.jboss.resteasy.core.ResourceLocatorInvoker.createResource(ResourceLocatorInvoker.java:81)
org.jboss.resteasy.core.ResourceLocatorInvoker.createResource(ResourceLocatorInvoker.java:60)
org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:102)
org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:356)
org.jboss.resteasy.core.SynchronousDispatcher.invokePropagateNotFound(SynchronousDispatcher.java:217)
org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:224)
org.jboss.resteasy.plugins.server.servlet.FilterDispatcher.doFilter(FilterDispatcher.java:62)
org.camunda.bpm.engine.rest.filter.CacheControlFilter.doFilter(CacheControlFilter.java:41)

Appreciate help in this regard.
Thanks,
Roopali