How to replace HashMap Values while iterating over them in Java

Question

I am using a Runnable to automatically subtract 20 from a players cooldown every second, but I have no idea how to replace the value of a value as I iterate through it. How can I have it update the value of each key?

public class CoolDownTimer implements Runnable {     @Override     public void run() {         for (Long l : playerCooldowns.values()) {             l = l - 20;             playerCooldowns.put(Key???, l);         }     }  } 

Answer 1

Using Java 8:

map.replaceAll((k, v) -> v - 20); 

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Using Java 7 or older:

You can iterate over the entries and update the values as follows:

for (Map.Entry<Key, Long> entry : playerCooldowns.entrySet()) {     entry.setValue(entry.getValue() - 20); }