The following NPE is observed when relatedParty is not being passed in API body :

java.lang.NullPointerException: null
{{ at org.onap.nbi.apis.serviceorder.workflow.CheckOrderConsistenceManager.getCustomerFromServiceOrder(CheckOrderConsistenceManager.java:99) ~[classes!/:1.0.0-SNAPSHOT]}}
{{ at org.onap.nbi.apis.serviceorder.workflow.CheckOrderConsistenceManager.manageCustomer(CheckOrderConsistenceManager.java:80) ~[classes!/:1.0.0-SNAPSHOT]}}
{{ at org.onap.nbi.apis.serviceorder.workflow.CheckOrderConsistenceManager.checkServiceOrder(CheckOrderConsistenceManager.java:27) ~[classes!/:1.0.0-SNAPSHOT]}}
{{ at org.onap.nbi.apis.serviceorder.ServiceOrderResource.scheduleCheckServiceOrders(ServiceOrderResource.java:133) ~[classes!/:1.0.0-SNAPSHOT]}}
{{ at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]}}
{{ at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_121]}}
{{ at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]}}
{{ at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]}}
{{ at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:65) ~[spring-context-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]}}
{{ at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54) ~[spring-context-4.3.14.RELEASE.jar!/:4.3.14.RELEASE]}}
{{ at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_121]}}
{{ at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [na:1.8.0_121]}}
{{ at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_121]}}
{{ at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [na:1.8.0_121]}}
{{ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_121]}}
{{ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_121]}}
{{ at java.lang.Thread.run(Thread.java:745) [na:1.8.0_121]}}

The problem is in the CheckOrderConsistenceManager class and I fixed it by adding a check to bypass the for loop if the relatedParty is not passed:

if (serviceOrder.getRelatedParty() != null)
{
  for (RelatedParty relatedParty : serviceOrder.getRelatedParty()) {
  if ("ONAPcustomer".equalsIgnoreCase(relatedParty.getRole())) {
  return relatedParty;
  }
  }
}