On Jul 4, 2018, at 5:42 AM, Zheka Kozlov <orionllm...@gmail.com> wrote:
>
> I noticed dead code in java.util.HashMap.merge():
>
> public V merge(K key, V value,
> BiFunction<? super V, ? super V, ? extends V>
> remappingFunction) {
> if (value == null)
> throw new NullPointerException();
>
> ...
>
> if (value != null) { *// Condition ' value != null' is always true*
> if (t != null)
> t.putTreeVal(this, tab, hash, key, value);
> else {
> tab[i] = newNode(hash, key, value, first);
> if (binCount >= TREEIFY_THRESHOLD - 1)
> treeifyBin(tab, hash);
> }
> ++modCount;
> ++size;
> afterNodeInsertion(true);
> }
> return value;
> }
>
> The code in the if branch will never be executed because `value` was
> previously checked at the beginning of the method.
>
> Is this a mistake?
You mean it will ALWAYS be executed. Yes, it looks to me like the ‘if’ is
useless.
