- kubeadm: removed preflight check for existence of the conntrack binary, as conntrack is no longer a kube-proxy dependency in version 1.32 and newer. ([#126953](https://github.com/kubernetes/kubernetes/pull/126953), [@aroradaman](https://github.com/aroradaman))

- Optimized kube-proxy conntrack cleanup logic, reducing the time complexity of deleting stale UDP entries. This significantly improves performance when there are many stale connections to clean up. ([#135511](https://github.com/kubernetes/kubernetes/pull/135511), [@aojea](http...

- Fixes a regression introduced in 1.29 where conntrack entries for UDP connections
  to deleted pods did not get cleaned up correctly, which could (among other things)

   * 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.

The [Hasher] interface type defines the contract between values of a
particular type and future hash-based data structures such as hash

        .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(

        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();

    }
  }

  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;
      }