import java.util.HashMap;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeMap;
public class MyClass {
public static void main(String args[]) {
HashMap<String, Integer> hmp = new HashMap<String, Integer>();
hmp.put("java", 4);
hmp.put("c++", 2);
hmp.put("c", 6);
hmp.put("python", 5);
hmp.put("c#", 1);
hmp.put("php", 3);
System.out.println("HashMap before sorting");
hmp.entrySet().forEach(entry -> {
System.out.println(entry.getKey() + " " + entry.getValue());
});
TreeMap<String, Integer> tm = new TreeMap<>(hmp);
Set<Entry<String, Integer>> st_by_keys = tm.entrySet();
System.out.println("HashMap after sorting by keys");
for(Entry<String, Integer> entry : st_by_keys){
System.out.println(entry.getKey() + " ==> " + entry.getValue());
}
}
}
/*
run:
HashMap before sorting
c# 1
c++ 2
python 5
java 4
c 6
php 3
HashMap after sorting by keys
c ==> 6
c# ==> 1
c++ ==> 2
java ==> 4
php ==> 3
python ==> 5
*/