A DESCRIPTION OF THE PROBLEM :
The implementation requirements for Map::compute reads:

 V oldValue = map.get(key);
 V newValue = remappingFunction.apply(key, oldValue);
 if (oldValue != null ) {
    if (newValue != null)
       map.put(key, newValue);
    else
       map.remove(key);
 } else {
    if (newValue != null)
       map.put(key, newValue);
    else
       return null;
 }

However, it's weird that the code only returns when (oldValue == null && newValue == null). The problem is that the code doesn't return anything otherwise. I think the better way is:

 V oldValue = map.get(key);
 V newValue = remappingFunction.apply(key, oldValue);
 if (oldValue != null ) {
    if (newValue != null)
       map.put(key, newValue);
    else
       map.remove(key);
 } else {
    if (newValue != null)
       map.put(key, newValue);
 }
 return newValue;

PS. This issue meant to target the documentation of the core libraries, but I couldn't find it in the "Subcomponent" list. So I chose "guides: Documentation related to Guides" instead.


FREQUENCY : always