}
  }

  // 128 - [chars 0x0000 to 0x007f]
  private static final long ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS = 0x007f - 0x0000 + 1;

  // 128
  private static final long EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT =
      ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS;

  // 1920 [chars 0x0080 to 0x07FF]
  private static final long TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS = 0x07FF - 0x0080 + 1;

  // 18,304

        .putChar((char) 0x0100)
        .putChar((char) 0x0000)
        .putChar((char) 0x0000);
    assertEquals(hashCode, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();
    hasher.putBytes(new byte[] {0x01, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00});
    assertEquals(hashCode, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();
    hasher.putLong(0x0000000001000101L);

    return ((0xFL << 4) | (codePoint >>> 18))
        | ((0x80L | (0x3F & (codePoint >>> 12))) << 8)
        | ((0x80L | (0x3F & (codePoint >>> 6))) << 16)
        | ((0x80L | (0x3F & codePoint)) << 24);
  }

  private static long charToThreeUtf8Bytes(char c) {
    return ((0x7L << 5) | (c >>> 12))
        | ((0x80 | (0x3F & (c >>> 6))) << 8)
        | ((0x80 | (0x3F & c)) << 16);
  }

# ADR-0008 - Use NullAway for null checking

## Status

- ACCEPTED on 2025-08-06

## Context

Our codebase uses `null` extensively to represent an absence of value or optionality of the argument.
We utilize nullness annotations in Java code and somewhat rely on IDE warnings to guide us.
However, the Java code we have is not fully annotated, which causes several consequences:
* IDE warnings can be misleading

    Random rng = new Random(0);
    for (int z = 0; z < 100; z++) {
      int[] codePoints = new int[rng.nextInt(8)];
      for (int i = 0; i < codePoints.length; i++) {
        do {
          codePoints[i] = rng.nextInt(0x800);
        } while (!Character.isValidCodePoint(codePoints[i])
            || (codePoints[i] >= Character.MIN_SURROGATE
                && codePoints[i] <= Character.MAX_SURROGATE));
      }

    Random rng = new Random(0);
    for (int z = 0; z < 100; z++) {
      int[] codePoints = new int[rng.nextInt(8)];
      for (int i = 0; i < codePoints.length; i++) {
        do {
          codePoints[i] = rng.nextInt(0x800);
        } while (!Character.isValidCodePoint(codePoints[i])
            || (codePoints[i] >= Character.MIN_SURROGATE
                && codePoints[i] <= Character.MAX_SURROGATE));
      }

    }

    String validTeredoAddress = "2001:0000:4136:e378:8000:63bf:3fff:fdd2";
    String serverStr = "65.54.227.120";
    String clientStr = "192.0.2.45";
    int port = 40000;
    int flags = 0x8000;

    InetAddress ip = InetAddresses.forString(validTeredoAddress);
    assertTrue(InetAddresses.isTeredoAddress((Inet6Address) ip));
    InetAddresses.TeredoInfo teredo = InetAddresses.getTeredoInfo((Inet6Address) ip);