We help IT Professionals succeed at work.
Get Started

Performance issue while iterating with streams

srikotesh
srikotesh asked
on
106 Views
Last Modified: 2016-09-14
Hi Experts,

I have written the below program using java7 and java8

Collections are giving me result quickly when i compared with streams
Is any thing wrong in my code.
can some one suggest me what exactly the issue with streams iteration.

Collections is taking only 16 milliseconds
FROM STREAMS
localCaloricDishesName  [EggCurry, BeatRootCurry, LadyFinger]
109 millis

package com.java8;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

public class StreamAndFilter  {

	public static void main1(String[] args) {
		Long startTime = System.currentTimeMillis();	
		List<Dish> menu = new ArrayList<>();
		menu.add(new Dish("CarrotCurry",405));
		menu.add(new Dish("BeatRootCurry",215));
		menu.add(new Dish("PotatosCurry",450));
		menu.add(new Dish("TamatoCurry",500));
		menu.add(new Dish("LadyFinger",300));
		menu.add(new Dish("EggCurry",200));
		
		List<Dish> localCaloricDishesName = new ArrayList<>();
		
		for (Dish dish : menu) {
			if(dish.getCalories()<400){
				localCaloricDishesName.add(dish);
			}
		}
		
		Collections.sort(localCaloricDishesName,new Comparator<Dish>() {

			@Override
			public int compare(Dish o1, Dish o2) {
				// TODO Auto-generated method stub
				return Integer.compare(o1.getCalories(), o2.getCalories());
			}
			
		});
		
		List<String> curryNames = new ArrayList<String>();
		for (Dish dish : localCaloricDishesName) {
			curryNames.add(dish.getDishName());
		}
		
		System.out.println("curryNames"+curryNames);;
		System.out.println(System.currentTimeMillis()-startTime);
	}
	
	public static void main(String[] args) {
		System.out.println("FROM STREAMS");
		Long startTime = System.currentTimeMillis();
		List<Dish> menu = new ArrayList<>();
		menu.add(new Dish("CarrotCurry",405));
		menu.add(new Dish("BeatRootCurry",215));
		menu.add(new Dish("PotatosCurry",450));
		menu.add(new Dish("TamatoCurry",500));
		menu.add(new Dish("LadyFinger",300));
		menu.add(new Dish("EggCurry",200));
		
		List<String> localCaloricDishesName = 
				menu.stream()
				.filter(d->d.getCalories()<400)
				.sorted(Comparator.comparing(Dish :: getCalories))
				.map(Dish::getDishName)
				.collect(Collectors.toList());
		
		System.out.println("localCaloricDishesName  "+localCaloricDishesName);
		System.out.println(System.currentTimeMillis()-startTime);		
	}
}

Open in new window

Comment
Watch Question
Senior Java Architect
Commented:
This problem has been solved!
Unlock 1 Answer and 5 Comments.
See Answer
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant
Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE