this is the controller and repository

LeagueController.java && LeagueRepository.java

package com.intraedge.project.prok.controllers;

import java.util.List;

import javax.validation.Valid;

import org.bson.types.ObjectId;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.intraedge.project.prok.domain.League;
import com.intraedge.project.prok.repositories.LeagueRepository;

@RestController
//@RequestMapping("/leagues")
public class LeagueController {
	
	@Autowired
	private LeagueRepository leagueRepository;
	
	@RequestMapping(value="/leagues", method=RequestMethod.GET)
	public List<League> getLeagues(){
		return leagueRepository.findAll();
	}
	
	@RequestMapping(value="/{id}", method=RequestMethod.GET)
	public League getLeagueById(@PathVariable("id") ObjectId _id) {
		return leagueRepository.findBy_id(_id);
	}
	
	@RequestMapping(value="/{id}", method=RequestMethod.PUT)
	public League modifyLeagueById(@PathVariable("id") ObjectId _id, @Valid @RequestBody League league) {
		league.set_id(_id);
		leagueRepository.save(league);
		return league;
	}
	
	@RequestMapping(value="/", method=RequestMethod.POST)
	public League createLeague(@Valid @RequestBody League league) {
		league.set_id(ObjectId.get());
		leagueRepository.save(league);
		return league;
	}
	
	@RequestMapping(value="/{id}", method=RequestMethod.DELETE)
	public void deleteLeague(@PathVariable ObjectId _id) {
		leagueRepository.delete(leagueRepository.findBy_id(_id));
	}

}

//Repository LeagueRepository
package com.intraedge.project.prok.repositories;

import org.bson.types.ObjectId;
import org.springframework.data.mongodb.repository.MongoRepository;

import com.intraedge.project.prok.domain.League;

public interface LeagueRepository extends MongoRepository<League, String> {
	League findBy_id(ObjectId _id);

}