guava/src/com/google/common/collect/RegularImmutableMap.java
static <K, V> ImmutableMap<K, V> fromEntryArray(int n, Entry<K, V>[] entryArray) {
    checkPositionIndex(n, entryArray.length);
    if (n == 0) {
      return (RegularImmutableMap<K, V>) EMPTY;
    }
    Entry<K, V>[] entries;
    if (n == entryArray.length) {
      entries = entryArray;
    } else {
      entries = createEntryArray(n);
    }
    int tableSize = Hashing.closedTableSize(n, MAX_LOAD_FACTOR);
    ImmutableMapEntry<K, V>[] table = createEntryArray(tableSize);
    int mask = tableSize - 1;
    for (int entryIndex = 0; entryIndex < n; entryIndex++) {
      Entry<K, V> entry = entryArray[entryIndex];
      K key = entry.getKey();
      V value = entry.getValue();
      checkEntryNotNull(key, value);
      int tableIndex = Hashing.smear(key.hashCode()) & mask;
      @Nullable ImmutableMapEntry<K, V> existing = table[tableIndex];
      // prepend, not append, so the entries can be immutable
      ImmutableMapEntry<K, V> newEntry =
          (existing == null)
              ? makeImmutable(entry, key, value)
              : new NonTerminalImmutableMapEntry<K, V>(key, value, existing);
      table[tableIndex] = newEntry;
      entries[entryIndex] = newEntry;
      int bucketSize = checkNoConflictInKeyBucket(key, newEntry, existing);
      if (bucketSize > MAX_HASH_BUCKET_LENGTH) {
        // probable hash flooding attack, fall back to j.u.HM based implementation and use its
        // implementation of hash flooding protection
        return JdkBackedImmutableMap.create(n, entryArray);
      }
    }
    return new RegularImmutableMap<>(entries, table, mask);
  }
static <K, V> ImmutableMap<K, V> fromEntryArray(int n, Entry<K, V>[] entryArray) {
    checkPositionIndex(n, entryArray.length);
    if (n == 0) {
      return (RegularImmutableMap<K, V>) EMPTY;
    }
    Entry<K, V>[] entries;
    if (n == entryArray.length) {
      entries = entryArray;
    } else {
      entries = createEntryArray(n);
    }
    int tableSize = Hashing.closedTableSize(n, MAX_LOAD_FACTOR);
    ImmutableMapEntry<K, V>[] table = createEntryArray(tableSize);
    int mask = tableSize - 1;
    for (int entryIndex = 0; entryIndex < n; entryIndex++) {
      Entry<K, V> entry = entryArray[entryIndex];
      K key = entry.getKey();
      V value = entry.getValue();
      checkEntryNotNull(key, value);
      int tableIndex = Hashing.smear(key.hashCode()) & mask;
      @Nullable ImmutableMapEntry<K, V> existing = table[tableIndex];
      // prepend, not append, so the entries can be immutable
      ImmutableMapEntry<K, V> newEntry =
          (existing == null)
              ? makeImmutable(entry, key, value)
              : new NonTerminalImmutableMapEntry<K, V>(key, value, existing);
      table[tableIndex] = newEntry;
      entries[entryIndex] = newEntry;
      int bucketSize = checkNoConflictInKeyBucket(key, newEntry, existing);
      if (bucketSize > MAX_HASH_BUCKET_LENGTH) {
        // probable hash flooding attack, fall back to j.u.HM based implementation and use its
        // implementation of hash flooding protection
        return JdkBackedImmutableMap.create(n, entryArray);
      }
    }
    return new RegularImmutableMap<>(entries, table, mask);
  }
Creates an ImmutableMap from the first n entries in entryArray. This implementation may replace
the entries in entryArray with its own entry objects (though they will have the same key/value
contents), and may take ownership of entryArray.