ManagementGraph jobManagementGraph = jobmanager.getManagementGraph(jobEvent.getJobID());
ManagementGroupVertex groupvertex = jobManagementGraph.getGroupVertexByID(groupvertexId);
// Serialize ManagementGraph to json
wrt.write("{\"groupvertex\": "+groupvertex.toJson()+",");
wrt.write("\"verticetimes\": {");
boolean first = true;
for(ManagementGroupVertex groupVertex : jobManagementGraph.getGroupVerticesInTopologicalOrder()) {