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https://www.youtube.com/watch?v=lwa448Kf-NQ&list=UUhwKlOVR041tngjerWxVccw
TreeMapExample.java
Output
https://www.youtube.com/watch?v=lwa448Kf-NQ&list=UUhwKlOVR041tngjerWxVccw
TreeMapExample.java
import java.util.Set; import java.util.TreeMap; /* * Example of keySet() method. */ public class TreeMapExample { public static void main( String[] args ) { TreeMap<Integer, String> treeMap = new TreeMap<Integer, String>(); treeMap.put(1, "Cat"); treeMap.put(2, "Dog"); treeMap.put(4, "Apple"); treeMap.put(3, "Ball"); System.out.println("treeMap : " + treeMap +"\n"); /* * 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 iteration over the * set is in progress (except through the iterator's own remove * operation), the results of the iteration are undefined. The set * supports element removal, which removes the corresponding mapping * from the map, via the Iterator.remove, Set.remove, removeAll, * retainAll, and clear operations. It does not support the add or * addAll operations. */ Set<Integer> set = treeMap.keySet(); System.out.println("set : " + set + "\n"); for( Integer key : set ) { System.out.println(key); } } }
treeMap : {1=Cat, 2=Dog, 3=Ball, 4=Apple} set : [1, 2, 3, 4] 1 2 3 4
https://sites.google.com/site/javaee4321/java-collections/TreeMapDemoKeySet.zip?attredirects=0&d=1
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