Find the key value with respect to value by using comparing with each item in Map List in Java

I have a problem about finding key value with respect to value by using comparing with each item in Map List in Java.

If multiple key values with the same value, I want to get the highest character value. If all key values are different, I want to get a key with the highest value.

Here is my screenshot shown below.

p/11
a/16  -> Here is the result
s/12
d/10
u/13

b/20
c/20  -> Here is the result
d/1

I have a problem in compare part which I cannot handle with.

How can I fix my issue?

Here is my code snippet shown below.

Map.Entry<Character, Integer> maxEntry = null;
for(Map.Entry<Character, Integer> entry : list.entrySet()){
            
    if (maxEntry == null || (entry.getKey()
          .compareTo(maxEntry.getKey()) >= 0  && entry.getValue()
          .compareTo(maxEntry.getValue()) >= 0)) {
              maxEntry = entry;            
    }
            
    System.out.println(entry.getKey() + "/" + entry.getValue());
}
        
return maxEntry.getKey();

Answer

Assuming you have a map Map<Character,Integer> and want to return a Character, taking your sample input as an example:

Map<Character,Integer> map1 = Map.of('p', 11,
                                     'a', 16,
                                     's', 12,
                                     'd', 10,
                                     'u', 13);

Map<Character,Integer> map2 = Map.of('b',20,
                                     'c',20,
                                     'd', 1);

you can use stream.max() which takes a comparator, where you could pass a comparator composed by a value-comparator and key-comparator using Comparator.thenComparing:

import java.util.Comparator;
import java.util.Map;
import java.util.Map.Entry;

....


public static Character getMax(Map<Character,Integer> myMap) {
    Comparator<Entry<Character,Integer>> byKey   = Entry.comparingByKey();
    Comparator<Entry<Character,Integer>> byValue = Entry.comparingByValue();

    return myMap.entrySet()
            .stream()
            .max(byValue.thenComparing(byKey))
            .map(Entry::getKey)
            .orElse(null);
}