difference between pathvariable and requestparam code example

Example: pathvariable and requestparam together

@RequestMapping(value = "/child/{nodeId}/{relType}",method = RequestMethod.GET, produces=MediaType.APPLICATION_JSON)    
        public Iterable<Node> getConnectedNodes(@RequestParam(value="page", required=false) int page, @RequestParam(value="size", required=false) int size, @PathVariable("nodeId") String nodeId, @PathVariable("relType") String relType) {
            return nodeService.getConnectedNodes(nodeId, relType,page,size);    

}