private static Key parseBToKey1(
      TestSerializationB serialization, @Nullable SecretKeyAccess access)
      throws GeneralSecurityException {
    if (!B_1.equals(serialization.getObjectIdentifier())) {
      throw new GeneralSecurityException("Wrong object identifier");
    }
    SecretKeyAccess.requireAccess(access);
    return new TestKey1();
  }
Thread safety tests for {@link MutableSerializationRegistry}.
java_src/src/test/java/com/google/crypto/tink/internal/MutableSerializationRegistryMultithreadTest.java