* documentation.
   */
  public void add(Runnable runnable, Executor executor) {
    // Fail fast on a null. We throw NPE here because the contract of Executor states that it throws
    // NPE on null listener, so we propagate that contract up into the add method as well.
    checkNotNull(runnable, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");

  * When annotating existing internal code, use `org.jetbrains.annotations.Contract`, e.g. `@Contract(null -> null; !null -> !null)`.
      When doing so, still annotate nullable parameters and the return type as `@Nullable`.
  * Do not use `@Contract` for public APIs.
  * For polynull public APIs, the solution has to be decided on a case-by-case basis.

    }
  }

  public void testNoNullValues() {
    for (StandardSystemProperty property : StandardSystemProperty.values()) {
      // Even though the contract in System.getProperties() specifies that a value will exist for
      // all of the listed keys, for some reason the "java.compiler" key returns null in some JVMs.
      if (property == JAVA_COMPILER) {
        continue;
      }

        assertEquals("nested_value", ((Map<String, Object>) result.get("nested")).get("nested_key"));
    }

    // Test interface contract consistency
    @Test
    public void test_interfaceContract() {
        TestSearchLogEvent event = new TestSearchLogEvent("contract-id", 5L, "contract-type");

        // Test consistency of returned values
        String id1 = event.getId();
        String id2 = event.getId();

        .isWithin(ALLOWED_ERROR)
        .of(45.6);
  }

  public void testScale_indexes_varargs_compute_doubleCollection() {
    // Note that we specify index 1 twice, which by the method contract should be ignored.
    assertThat(Quantiles.scale(10).indexes(0, 10, 5, 1, 8, 1).compute(SIXTEEN_SQUARES_DOUBLES))
        .comparingValuesUsing(QUANTILE_CORRESPONDENCE)
        .containsExactly(

        .isWithin(ALLOWED_ERROR)
        .of(45.6);
  }

  public void testScale_indexes_varargs_compute_doubleCollection() {
    // Note that we specify index 1 twice, which by the method contract should be ignored.
    assertThat(Quantiles.scale(10).indexes(0, 10, 5, 1, 8, 1).compute(SIXTEEN_SQUARES_DOUBLES))
        .comparingValuesUsing(QUANTILE_CORRESPONDENCE)
        .containsExactly(

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

    }
  }

  public void testNoNullValues() {
    for (StandardSystemProperty property : StandardSystemProperty.values()) {
      // Even though the contract in System.getProperties() specifies that a value will exist for
      // all of the listed keys, for some reason the "java.compiler" key returns null in some JVMs.
      if (property == JAVA_COMPILER) {
        continue;
      }

This policy protects our limited review budget, allowing us to invest our attention wisely.

A pull request is not a finished product—it is the start of a conversation, and an implied contract: we promise to provide thoughtful feedback, and we expect the contributor to engage with us in return.

## What we expect from contributors

  }

  interface A {}

  interface B {}

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(newDelegatingList(LIST1))
        // Actually, this violates List#equals contract.
        // But whatever, no one is going to proxy List (hopefully).
        .addEqualityGroup(newDelegatingList(LIST1))
        .addEqualityGroup(newDelegatingList(LIST2))
        .addEqualityGroup(