# 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

    assertThat(record.getMessage()).isEqualTo("message");
    assertThat(record.getThrown()).isEqualTo(EXCEPTION);
  }

  public void testConcurrentModification() throws Exception {
    // Tests for the absence of a bug where logging while iterating over the
    // stored log records causes a ConcurrentModificationException
    assertTrue(handler.getStoredLogRecords().isEmpty());
    ExampleClassUnderTest.foo();

    assertThat(record.getMessage()).isEqualTo("message");
    assertThat(record.getThrown()).isEqualTo(EXCEPTION);
  }

  public void testConcurrentModification() throws Exception {
    // Tests for the absence of a bug where logging while iterating over the
    // stored log records causes a ConcurrentModificationException
    assertTrue(handler.getStoredLogRecords().isEmpty());
    ExampleClassUnderTest.foo();

        // 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")

  }

  /** 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.
     *

   * AbstractListTester isn't enough because many tests that run on lists don't
   * extends AbstractListTester.) We could also iterate over all elements to
   * verify absence
   */
  protected void expectMissing(E... elements) {
    for (E element : elements) {
      assertFalse("Should not contain " + element, actualContents().contains(element));
    }
  }

 * caller's responsibility.
 *
 * @author Paul Marks
 * @since 10.0
 */
@Immutable
@GwtCompatible
public final class HostAndPort implements Serializable {
  /** Magic value indicating the absence of a port number. */
  private static final int NO_PORT = -1;

  /** Hostname, IPv4/IPv6 literal, or unvalidated nonsense. */
  private final String host;

   * AbstractListTester isn't enough because many tests that run on lists don't
   * extends AbstractListTester.) We could also iterate over all elements to
   * verify absence
   */
  protected void expectMissing(E... elements) {
    for (E element : elements) {
      assertFalse("Should not contain " + element, actualContents().contains(element));
    }
  }

 * 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> {