package com.baeldung.map.entry; import java.util.HashMap; import java.util.Map; public class MapEntryEfficiencyExample { public static void main(String[] args) { MapEntryEfficiencyExample mapEntryEfficiencyExample = new MapEntryEfficiencyExample(); Map map = new HashMap<>(); map.put("Robert C. Martin", "Clean Code"); map.put("Joshua Bloch", "Effective Java"); System.out.println("Iterating Using Map.KeySet - 2 operations"); mapEntryEfficiencyExample.usingKeySet(map); System.out.println("Iterating Using Map.Entry - 1 operation"); mapEntryEfficiencyExample.usingEntrySet(map); } public void usingKeySet(Map bookMap) { for (String key : bookMap.keySet()) { System.out.println("key: " + key + " value: " + bookMap.get(key)); } } public void usingEntrySet(Map bookMap) { for (Map.Entry book: bookMap.entrySet()) { System.out.println("key: " + book.getKey() + " value: " + book.getValue()); } } }