result.addFailure(new RuntimeException("RuntimeException"));
        result.addFailure(new IllegalStateException("IllegalStateException"));
        result.addFailure(new NullPointerException("NullPointerException"));

        assertEquals(4, result.getFailures().size());
        assertTrue(result.getFailures().get(0) instanceof Exception);
        assertTrue(result.getFailures().get(1) instanceof RuntimeException);

    @Test
    void testPropertiesClear() {
        // Test for issue #11552: NullPointerException when clearing properties
        Model model = new Model();
        model.addProperty("key1", "value1");
        model.addProperty("key2", "value2");
        assertEquals(2, model.getProperties().size());

        // This should not throw NullPointerException
        model.getProperties().clear();

   *
   * @throws NullPointerException if the element is null
   */
  public static <E> ImmutableList<E> of(E e1) {
    return new SingletonImmutableList<>(e1);
  }

  /**
   * Returns an immutable list containing the given elements, in order.
   *
   * @throws NullPointerException if any element is null
   */
  public static <E> ImmutableList<E> of(E e1, E e2) {

    assertThrows(NullPointerException.class, () -> builder.put(null, 1));
    assertThrows(NullPointerException.class, () -> builder.putAll(null, Arrays.asList(1, 2, 3)));
    assertThrows(NullPointerException.class, () -> builder.putAll(null, 1, 2, 3));
    assertThrows(
        NullPointerException.class, () -> builder.putAll((Multimap<String, Integer>) toPut));
  }

     * Returns the value of a specific attribute.
     *
     * @param name the name of the attribute to retrieve
     * @return the attribute value, or {@code null} if the attribute doesn't exist
     * @throws NullPointerException if name is null
     */
    @Nullable
    String attribute(@Nonnull String name);

    /**
     * Returns an immutable list of all child nodes.
     *

@GwtCompatible
final class CollectPreconditions {

  static void checkEntryNotNull(@Nullable Object key, @Nullable Object value) {
    if (key == null) {
      throw new NullPointerException("null key in entry: null=" + value);
    } else if (value == null) {
      throw new NullPointerException("null value in entry: " + key + "=null");
    }
  }

  @CanIgnoreReturnValue
  static int checkNonnegative(int value, String name) {
    if (value < 0) {

    assertSame(canonical, pool.intern(canonical));
    assertSame(canonical, pool.intern(not));
  }

  public void testStrong_null() {
    Interner<String> pool = Interners.newStrongInterner();
    assertThrows(NullPointerException.class, () -> pool.intern(null));
  }

  public void testStrong_builder() {
    int concurrencyLevel = 42;
    Interner<Object> interner =

    assertSame(canonical, pool.intern(canonical));
    assertSame(canonical, pool.intern(not));
  }

  public void testStrong_null() {
    Interner<String> pool = Interners.newStrongInterner();
    assertThrows(NullPointerException.class, () -> pool.intern(null));
  }

  public void testStrong_builder() {
    int concurrencyLevel = 42;
    Interner<Object> interner =

* IDE warnings can be misleading
* Redundant null checks may increase binary size, hurt performance, and increase cognitive load for readers
* Missing null checks may cause NullPointerException
* Bridging with Kotlin code is polluted with platform types
* Some public APIs have incorrect nullability annotations (both overly restrictive and overly permissive)

     *
     * @throws NullPointerException if {@code key}, {@code values}, or any element in {@code values}
     *     is null. The builder is left in an invalid state.
     */
    @CanIgnoreReturnValue
    public Builder<K, V> putAll(K key, Iterable<? extends V> values) {
      if (key == null) {
        throw new NullPointerException("null key in entry: null=" + Iterables.toString(values));
      }