checkNotNull(value2);
    checkArgument(!Objects.equals(value1, value2), "Duplicate value provided.");
    distinctValues.replaceValues(type, ImmutableList.of(value1, value2));
    setDefault(type, value1);
    return this;
  }

  /**
   * Tests that {@code cls} properly checks null on all constructor and method parameters that
   * aren't annotated nullable (according to the rules of {@link NullPointerTester}). In details:
   *

        // Test minimum value
        event.setVersionNo(Long.MIN_VALUE);
        assertEquals(Long.valueOf(Long.MIN_VALUE), event.getVersionNo());

        // Test zero
        event.setVersionNo(0L);
        assertEquals(Long.valueOf(0L), event.getVersionNo());

        // Test maximum value
        event.setVersionNo(Long.MAX_VALUE);
        assertEquals(Long.valueOf(Long.MAX_VALUE), event.getVersionNo());

        System.setProperty("custom.prop.one", "value1");
        System.setProperty("custom.prop.two", "value2");
        System.setProperty("other.property", "value3");

        // Test with regex pattern
        execJob.testAddFessCustomSystemProperties(cmdList, "custom\\.prop\\..*");

        assertEquals(2, cmdList.size());
        assertTrue(cmdList.contains("-Dcustom.prop.one=value1"));

    }

    static final class DuplicateKey {
      private final Object key;
      private final Object value1;
      private final Object value2;

      DuplicateKey(Object key, Object value1, Object value2) {
        this.key = key;
        this.value1 = value1;
        this.value2 = value2;
      }

      IllegalArgumentException exception() {
        return new IllegalArgumentException(

        BooleanQuery.Builder boolQueryBuilder = new BooleanQuery.Builder();
        TermQuery termQuery1 = new TermQuery(new Term("field1", "value1"));
        TermQuery termQuery2 = new TermQuery(new Term("field2", "value2"));
        TermQuery termQuery3 = new TermQuery(new Term("field3", "value3"));

        boolQueryBuilder.add(termQuery1, BooleanClause.Occur.MUST);
        boolQueryBuilder.add(termQuery2, BooleanClause.Occur.SHOULD);

        String value1 = "a";
        String value2 = "b";
        String value3 = "c";
        settings.badword().add(value1);
        settings.badword().add(value2);
        settings.badword().add(value3);
        assertEquals(3, settings.badword().get(false).length);
        assertEquals(value1, settings.badword().get(false)[0]);
        assertEquals(value2, settings.badword().get(false)[1]);

        String key = "key";
        String value1 = "a";
        String value2 = "b";
        String value3 = "c";
        settings.array().add(key, value1);
        settings.array().add(key, value2);
        settings.array().add(key, value3);
        assertEquals(3, settings.array().get(key).length);
        assertEquals(value1, settings.array().get(key)[0]);
        assertEquals(value2, settings.array().get(key)[1]);

  /**
   * Sets two distinct values for {@code type}. These values can be used for both null pointer
   * testing and equals testing.
   *
   * @since 17.0
   */
  protected final <T> void setDistinctValues(Class<T> type, T value1, T value2) {
    tester.setDistinctValues(type, value1, value2);
  }

  /** Specifies that classes that satisfy the given predicate aren't tested for sanity. */

    private @Nullable V value;
    boolean loading = false;

    public DummyValueReference() {
      this.loading = true;
    }

    public DummyValueReference(V value) {
      this.value = value;
    }

    public static <K, V> DummyValueReference<K, V> create(V value) {
      return new DummyValueReference<>(value);
    }

    private @Nullable V value;
    boolean loading = false;

    public DummyValueReference() {
      this.loading = true;
    }

    public DummyValueReference(V value) {
      this.value = value;
    }

    public static <K, V> DummyValueReference<K, V> create(V value) {
      return new DummyValueReference<>(value);
    }