public void updateTaskDef(TaskDef taskDefinition) {
        TaskDef existing = metadataDAO.getTaskDef(taskDefinition.getName());
        if (existing == null) {
            throw new NotFoundException("No such task by name %s", taskDefinition.getName());
        }
        taskDefinition.setUpdatedBy(WorkflowContext.get().getClientApp());
        taskDefinition.setUpdateTime(System.currentTimeMillis());
        metadataDAO.updateTaskDef(taskDefinition);
    }
@param taskDefinition Task Definition to be updated
core/src/main/java/com/netflix/conductor/service/MetadataServiceImpl.java