@Override
  public V get(final Object key) {
    // throws NullPointerException if key null
    final int hash = entryCreator.keyHashCode(key, compareValues);
    return segmentFor(hash).get(key, hash);
  }
Returns the value to which the specified key is mapped, or {@code null} if this map contains no
mapping for the key.

<p>
More formally, if this map contains a mapping from a key {@code k} to a value {@code v} such
that {@code key.equals(k)}, then this method returns {@code v}; otherwise it returns
{@code null}. (There can be at most one such mapping.)

@throws NullPointerException if the specified key is null
geode-core/src/main/java/org/apache/geode/internal/util/concurrent/CustomEntryConcurrentHashMap.java