null error in availibility

.../main/java/com/example/schedulerapp/AvailabilityView.java

...pp/src/main/java/com/example/schedulerapp/Controller.java

...rApp/src/main/java/com/example/schedulerapp/Employee.java

...p/src/main/java/com/example/schedulerapp/ScheduleApp.java

...in/resources/com/example/schedulerapp/schedSidePanel.fxml