backend service error -- Hospital-Service-JDK11-2.0.0.jar

[jimmy003]

WARN MSF4JMessageProcessor:142 - Unmapped exception
java.lang.NullPointerException
at java.text.SimpleDateFormat.parse(SimpleDateFormat.java:1439)
at java.text.DateFormat.parse(DateFormat.java:364)
at org.wso2.service.hospital.HealthcareService.getAppointmentValidityTime(HealthcareService.java:96)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.wso2.msf4j.internal.router.HttpMethodInfo.invoke(HttpMethodInfo.java:108)
at org.wso2.msf4j.internal.MSF4JMessageProcessor.dispatchMethod(MSF4JMessageProcessor.java:129)
at org.wso2.msf4j.internal.MSF4JMessageProcessor.receive(MSF4JMessageProcessor.java:73)
at org.wso2.carbon.transport.http.netty.listener.WorkerPoolDispatchingSourceHandler$1.run(WorkerPoolDispatchingSourceHandler.java:127)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)