I am solving VRP with jsprit. I read solution from a file with VrpXmlReader
VehicleRoutingProblem.Builder problemBuilder = VehicleRoutingProblem.Builder.newInstance();
VrpXMLReader vrpXMLReader = new VrpXMLReader(problemBuilder, solutions);
vrpXMLReader.setSchemaValidation(false);
vrpXMLReader.read(initialSolutionStream);
VehicleRoutingProblem solutionProblem = problemBuilder.build();
but when the solution contains vehicle Breaks, I get an error
java.lang.IllegalArgumentException: The vehicle routing roblem already contains a vehicle break with id null. Please choose unique ids for each vehicle break.
How can I fix this?