Sort LinkedHashMap by Keys in Java

Last Updated : 11 Dec, 2020

LinkedHashMap maintains insertion order. Convert LinkedHashMap into TreeMap and after that print keys of TreeMap which are sorted in nature.

Example:

Input: linkedHashMap = {{5,4}, {3,44}, {4,15}, {1,20}, {2,11}}  Output:  key -> 1 : value -> 20  key -> 2 : value -> 11  key -> 3 : value -> 44  key -> 4 : value -> 15   key -> 5: value -> 4

Approach:

Take LinkedHashMap as an input.
Create new TreeMap.
Pass LinkedHashMap object into the constructor of TreeMap.
Print Keys of TreeMap object.

Below is the implementation of the above approach:

Java

// Sort LinkedHashMap by keys in Java import java.util.*; import java.io.*;  class GFG {     public static void main(String[] args)     {         LinkedHashMap<Integer, Integer> lMap             = new LinkedHashMap<>();          // adding key-value pairs to LinkedHashMap object         lMap.put(5, 4);         lMap.put(3, 44);         lMap.put(4, 15);         lMap.put(1, 20);         lMap.put(2, 11);         System.out.println("After Sorting :\n");          // convert to TreeMap         Map<Integer, Integer> map = new TreeMap<>(lMap);          // iterate acc to ascending order of keys         for (Integer sKey : map.keySet()) {             System.out.println("Key -> " + sKey                                + ":  Value -> "                                + lMap.get(sKey));         }     } }

Output

After Sorting :    Key -> 1:  Value -> 20  Key -> 2:  Value -> 11  Key -> 3:  Value -> 44  Key -> 4:  Value -> 15  Key -> 5:  Value -> 4

Sort LinkedHashMap by Keys in Java

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