Angular 2: Error while accessing JSON from HTTP

I am creating an application in angular 2. I am trying to access the json data via http in a service. But i am getting an error saying that

**GET http://localhost:4200/data/products.json 404 (Not Found)**

I have the data in the specified folder but i am unable to access it.

My service code is as follows.

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs';
import 'rxjs/add/operator/map';
import { Item } from './item';

@Injectable()
export class ItemService {
observableItems: Observable<Item[]>
allItems: Item[] = [];
selectedItems: Item[] = [];
errorMessage: string;
url = "http://localhost:4200/data/products.json";
constructor(private http:Http) { 
   this.observableItems = this.http.get(this.url).map((res: Response) => res.json());
   this.observableItems.subscribe(
             data => this.allItems = data,
         error =>  this.errorMessage = <any>error);
}
getItems(): Observable<Item[]> {
   return this.observableItems;
}
getSelectedItems(): Item[] {
   return this.selectedItems;
}   
    addItem(id:number): void {
       let item = this.allItems.find(ob => ob.id === id);
       if (this.selectedItems.indexOf(item) < 0) {     
      this.selectedItems.push(item);
   }
    }
    removeItem(id:number): void {
   let item = this.selectedItems.find(ob => ob.id === id);
   let itemIndex = this.selectedItems.indexOf(item);
       this.selectedItems.splice(itemIndex, 1);
    }
}