# ADR-0008 - Use NullAway for null checking

## Date

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

        // Test presence of flags
        assertTrue((flags & SecurityInfo.OWNER_SECURITY_INFO) != 0);
        assertTrue((flags & SecurityInfo.DACL_SECURITY_INFO) != 0);

        // Test absence of flags
        assertTrue((flags & SecurityInfo.GROUP_SECURITY_INFO) == 0);
        assertTrue((flags & SecurityInfo.SACL_SECURITY_INFO) == 0);
    }

    @Test
    @DisplayName("Test interface extends Decodable")

  ALLOWS_NULL_QUERIES,
  ALLOWS_NULL_VALUES(ALLOWS_NULL_QUERIES),

  /**
   * Indicates that a collection disallows certain elements (other than {@code null}, whose validity
   * as an element is indicated by the presence or absence of {@link #ALLOWS_NULL_VALUES}). From the
   * documentation for {@link Collection}:
   *
   * <blockquote>
   *
   * "Some collection implementations have restrictions on the elements that they may contain. For

     IMPLIED, STATUTORY, OR OTHER. THIS INCLUDES, WITHOUT LIMITATION,
     WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR
     PURPOSE, NON-INFRINGEMENT, ABSENCE OF LATENT OR OTHER DEFECTS,
     ACCURACY, OR THE PRESENCE OR ABSENCE OF ERRORS, WHETHER OR NOT
     KNOWN OR DISCOVERABLE. WHERE DISCLAIMERS OF WARRANTIES ARE NOT
     ALLOWED IN FULL OR IN PART, THIS DISCLAIMER MAY NOT APPLY TO YOU.

  }

  /** Equivalent to {@code add(-1)}. */
  public void decrement() {
    add(-1L);
  }

  /**
   * Returns the current sum. The returned value is NOT an atomic snapshot; invocation in
   * the absence of concurrent updates returns an accurate result, but concurrent updates that occur
   * while the sum is being calculated might not be incorporated.
   *
   * @return the sum
   */
  @Override
  public long sum() {

     * fail. Use a custom [HostnameVerifier] to ignore such problems.
     *
     * Other TLS features are still used but provide no security benefits in absence of the above
     * gaps. For example, an insecure TLS connection is capable of negotiating HTTP/2 with ALPN and
     * it also has a regular-looking handshake.
     *

tenants sending graphs to execute under another tenant’s identity.

The isolation mechanisms are the responsibility of the users to design and
implement, and therefore security issues deriving from their absence are not
considered a vulnerability in TensorFlow.

### Resource allocation

A denial of service caused by one model could bring down the entire server, but

 * a traditional {@code HashMap} implementation which stores keys and count values as map entries,
 * {@code ObjectCountHashMap} minimizes object allocation and reduces memory footprint.
 *
 * <p>In the absence of element deletions, this will iterate over elements in insertion order.
 */
@GwtCompatible
@NullMarked
class ObjectCountHashMap<K extends @Nullable Object> {

  types of tests cannot be setup, since the container used to run them cannot be
  reached or started.

  All of these operations will produce their own unique errors in the absence of
  a coordinated offline strategy. In addition, efforts to unite these failing
  behaviors behind a consistent user interface is much, much more difficult if

  }

  // this doc comment is a modified copy of the inherited doc comment,
  // without the reference to unlimited queues.
  /**
   * Returns the number of additional elements that this queue can ideally (in the absence of memory
   * or resource constraints) accept without blocking. This is always equal to the initial capacity
   * of this queue less the current {@code size} of this queue.
   *