public Set<K> keySet() Returns a Set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteratio
We shorten the code by using a var keyword in the for loop. Iteration over keysWe might want to iterate only over keys of a HashMap. Main.java import java.util.HashMap; import java.util.Map; import java.util.Set; void main() { Map<String, String> capitals = new HashMap<>(); ...
Using the entrySet() specifically is more powerful and yields better performance than using the keySet() for iteration over a HashMap in Java. This Java tutorial discusses thedifferent ways to iterate over aHashMapand compare the performance of each techniqueso we can make an informed decision. ...
System.out.println("TreeMap iteration Order:"); //iteration over map using for each loop for(Map.Entryentry: tm.entrySet()) { //getting keys and values using method //prints list in sorted order System.out.println(entry.getKey() + " = " +entry.getValue()); } } } 1. 2. 3. ...
keySet publicSet<K> keySet() Returns aSetview of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own...
Simply put, any access operation on the map results in an order such that the element that was accessed would appear last if an iteration were to be carried out right away. After the above examples, it should be obvious that aputAlloperation generates one entry access for each of the mappi...
* The set is backed by the map, so changes to the map are * reflected in the set, and vice-versa. If the map is modified * while an iteration over the set is in progress (except through * the iterator's own {@code remove} operation, or through the * {@code setValue} operation...
* while an iteration over the set is in progress (except through 1079 * the iterator's own <tt>remove</tt> operation, or through the 1080 * <tt>setValue</tt> operation on a map entry returned by the 1081 * iterator) the results of the iteration are undefined. The set 1082...
In case of HashMap, if we are iterating using its collection views (keySet, valueSet, entrySet) and modify the HashMap during iteration, we will get the ConcurrentModificationException. for (Map.Entry<String, Integer> entry : nameMap.entrySet()) { if (entry.getKey().startsWith("Temp-"...
Performance is likely to be just slightly below that of HashMap, due to the added expense of maintaining the linked list, with one exception: Iteration over the collection-views of a LinkedHashMap requires time proportional to the size of the map, regardless of its capacity. Iteration over a...