Java - avoiding null entries in map

import java.util.HashMap;
import java.util.Map;
import java.util.Optional;

public class MyClass {
    public static void main(String args[]) {
      Map<String, Optional<String>> myMap = new HashMap<>();
      myMap.put("this exists", Optional.of("abc"));
      myMap.put("this also exists", Optional.of("def"));
      myMap.put("this does not exist", Optional.empty());

      System.out.println(myMap);

      Optional<String> existing = myMap.get("this exists");
      if (existing.isPresent()) {
          System.out.println(existing.get());
      }
      else {
          System.out.println("Does not exist!");
      }

      Optional<String> nonExisting = myMap.get("this does not exist");
      if (nonExisting.isPresent()) {
          System.out.println(nonExisting.get());
      }
      else {
          System.out.println("Does not exist!");
      }

      Optional<String> shouldBeNull = myMap.get("no such entry");
      if (shouldBeNull == null) {
          System.out.println("It is null!");
      }
    }
}