Key from a Value in Java?

Question

Am I to understand there's no simple way to get a Key from a Value?

There are entire Stackoverflow debates over best practices and workarounds but they're making my head spin🤯

Please take a glance at my code and let me know if I'm missing something in the Hashmap lessons. Keep in mind my experience level is low🤓

Thanks 😊

https://code.sololearn.com/cPRILC2BHT0u/?ref=app

Answer 1

System.out.println(band.get("banjo"));

Here you get null because the get() method expects a key. "banjo" is a value.

System.out.println(band.get("Bubba"));
//output banjo

Another possibility to get the keys:

https://code.sololearn.com/c7BrlKiE1Uxp/?ref=app

Answer 2

Yes. That's the sense of a map.

Answer 3

Thank you for your response, Denise Roßberg , so am I to understand from your answer that trying to get the key by calling the value is the problem?

That you can only, ever, get a value by calling a key, and not the other way around?