sort hashmap using comparator

Author: joharbatta

HashMap/sortHashmap.java

@@ -0,0 +1,73 @@
+import java.util.*;
+
+class sortHashMap
+{
+    public static void main(String[] args) {
+        
+        Scanner sc=new Scanner(System.in);
+        int n=sc.nextInt();
+        int arr[]=new int[n];
+        for(int i=0;i<n;i++)
+        {
+            arr[i]=sc.nextInt();
+        }
+        HashMap<Integer,Integer> map=new HashMap<>();
+        
+        for(int i=0;i<n;i++)
+        {
+            map.put(arr[i],map.getOrDefault(arr[i],0)+1);
+        }
+
+        for(int i : map.keySet())
+        {
+            System.out.println(i+"--"+map.get(i));
+        }
+        List<Map.Entry<Integer, Integer> > list = 
+               new LinkedList<Map.Entry<Integer, Integer>>(map.entrySet());
+
+        Collections.sort(list, new Comparator<Map.Entry<Integer, Integer> >() 
+        { 
+            public int compare(Map.Entry<Integer, Integer> o1,  
+                               Map.Entry<Integer, Integer> o2) 
+            { 
+                //return (o1.getValue().compareTo(o2.getValue())); 
+                return o1.getValue()-o2.getValue();
+            } 
+        }); 
+
+
+        
+            System.out.println(list);
+            Collections.reverse(list);
+            System.out.println(list);
+
+            List<Integer> list1 = new LinkedList<>(map.keySet());
+
+            Collections.sort(list1, new Comparator<Integer>() 
+            { 
+                public int compare(Integer o1,Integer o2) 
+                { 
+                    //return (o1.getValue().compareTo(o2.getValue()));
+                    //for key sort 
+                    return o1-o2;
+                    //if -1 then less o1 than o2 0 zero 1 greator
+                    // at time of soting values swap according to this result
+                    //for values sort
+                    //return map.get(o1)-map.get(o1);
+                } 
+            }); 
+            System.out.println(list1);
+            HashMap<Integer,Integer> map1=new HashMap<>();
+
+            for(int i : list1)
+            {
+                map1.put(i,map.get(i));
+            }
+            System.out.println(map1);
+
+           
+
+
+        
+    }
+}