factoryField.setAccessible(true);
        factoryField.set(null, null);

        // Clear the protocol handlers cache
        Field handlersField = Handler.class.getDeclaredField("PROTOCOL_HANDLERS");
        handlersField.setAccessible(true);
        @SuppressWarnings("unchecked")
        Map<String, URLStreamHandler> handlers = (Map<String, URLStreamHandler>) handlersField.get(null);
        handlers.clear();
    }

    /**

        String value = request.getParameter("type");
        if (value == null) {
            final String servletPath = request.getServletPath();
            final String[] values = servletPath.replaceAll("/+", "/").split("/");
            if (values.length > 2) {
                value = values[2];
            }
        }
        if (value == null) {
            return FormatType.SEARCH;
        }

  /**
   * A word about using {@link Equivalence}, which automatically checks for {@code null} and
   * identical inputs: This sounds like it ought to be a problem here, since the goals of this class
   * include testing that {@code equals()} is reflexive and is tolerant of {@code null}. However,
   * there's no problem. The reason: {@link EqualsTester} tests {@code null} and identical inputs

    }

    if (requestMethod != "GET") {
      // Don't cache non-GET responses. We're technically allowed to cache HEAD, QUERY and some
      // POST requests, but the complexity of doing so is high and the benefit is low.
      return null
    }

    if (response.hasVaryAll()) {
      return null
    }

    val entry = Entry(response)
    var editor: DiskLruCache.Editor? = null
    try {

      if (oldValue != null) {
        if (throwIfDuplicateKeys) {
          throw conflictException("key", entryArray[i], entryArray[i].getKey() + "=" + oldValue);
        }
        if (duplicates == null) {
          duplicates = new HashMap<>();
        }
        duplicates.put(key, value);
        dupCount++;
      }
    }
    if (duplicates != null) {
      @SuppressWarnings({"rawtypes", "unchecked"})

        Mockito.verifyNoMoreInteractions(mock);
    }

    // --- Invalid/null usage: calling a method on null should throw NPE ---
    @Test
    void nullReference_throwsNullPointerException() {
        // Arrange
        SmbBasicFileInfo info = null;

        // Act & Assert: attempting to call any method on null should throw NPE
        Assertions.assertThrows(NullPointerException.class, () -> {

    private DefaultToolchainsReader reader = new DefaultToolchainsReader();

    @Test
    void testMergeNulls() {
        merger.merge(null, null, null);

        PersistedToolchains pt = new PersistedToolchains();
        merger.merge(pt, null, null);
        merger.merge(null, pt, null);
    }

    @Test
    void testMergeJdk() throws Exception {

        public String getUNCPath() {
            return null;
        }

        @Override
        public String getURLPath() {
            return null;
        }

        @Override
        public String getShare() {
            return null;
        }

        @Override
        public String getServerWithDfs() {
            return null;
        }

        @Override

    /**
     * Returns {@link Artifact} instance where to relocate to, or {@code null}.
     *
     * @param session The session, never {@code null}.
     * @param result The artifact descriptor result, never {@code null}.
     * @param model The artifact model, never {@code null}.
     * @return The {@link Artifact} to relocate to, or {@code null} if no relocation wanted.
     */

    this.singleValue = singleValue;
    this.inverse = null;
  }

  private SingletonImmutableBiMap(K singleKey, V singleValue, ImmutableBiMap<V, K> inverse) {
    this.singleKey = singleKey;
    this.singleValue = singleValue;
    this.inverse = inverse;
  }

  @Override
  public @Nullable V get(@Nullable Object key) {
    return singleKey.equals(key) ? singleValue : null;
  }

  @Override
  public int size() {