Program to Sort Map by key in Ascending order by using TreeMap, where key is Integer type.

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TreeMap is sorted by natural order of keys.

import java.util.Map; import java.util.TreeMap; /** * @author AnkitMittal * Copyright (c), AnkitMittal JavaMadeSoEasy.com * Main class */ public class SortMapByKeyAscending {    public static void main(String...a){        Map<Integer, Integer> treeMap = new TreeMap<Integer, Integer>();        treeMap.put(4, 1);        treeMap.put(2, 1);        treeMap.put(3, 1);        treeMap.put(5, 1);        System.out.println("treeMap : "+treeMap);           } } /*OUTPUT treeMap : {2=1, 3=1, 4=1, 5=1} */

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