Iterate through a HashMap "in chunks"

I need to iterate through a HashMap with 5000 items. After iterating on the 500th item, I need to do a sleep and then continue to the next 500 items.

Here is an example based on Java Map Example from Java Code Geeks:

import java.util.HashMap;
import java.util.Map;

public class HashMapExample {
    
    public static void main(String[] args) {
        Map<String, Integer> vehicles = new HashMap<>();
        
        // Add some vehicles.
        vehicles.put("BMW", 5);
        vehicles.put("Mercedes", 3);
        vehicles.put("Audi", 4);
        vehicles.put("Ford", 10);
        // add total of 5000 vehicles 
        
        // Iterate over all vehicles, using the keySet method.
        // Here I would like to do a sleep after iterating through 500 keys
        for(String key: vehicles.keySet())
            System.out.println(key + " - " + vehicles.get(key));
    }
}

Just have a counter variable to keep track of the number of iterations so far:

int cnt = 0;
for(String key: vehicles.keySet()) {
  System.out.println(key + " - " + vehicles.get(key));

  if (++cnt % 500 == 0) {
    Thread.sleep(sleepTime);  // throws InterruptedException; needs to be handled.
  }
}

Note that if you want both key and value in a loop, it is better to iterate the map's entrySet():

for(Map.Entry<String, Integer> entry: vehicles.entrySet()) {
  String key = entry.getKey();
  Integer value = entry.getValue();
  // ...
}