validator.accept(pa.getValue());
            stk.pop();
            stk.pop();
        });
        root.map(Activation::getJdk).ifPresent(jdk -> {
            stk.push(new ActivationFrame("jdk", Optional.empty()));
            validator.accept(jdk);
            stk.pop();
        });
    }

    private void validate20RawPlugins(
            ModelProblemCollector problems,

    return proxyClass.isInstance(arg)
        // Equal proxy instances should mostly be instance of proxyClass
        // Under some edge cases (such as the proxy of JDK types serialized and then deserialized)
        // the proxy type may not be the same.
        // We first check isProxyClass() so that the common case of comparing with non-proxy objects
        // is efficient.

      try {
        // 1.8, 9, 10, 11, 12 etc
        val version = jvmVersion.toInt()
        if (version >= 9) return null
      } catch (_: NumberFormatException) {
        // expected on >= JDK 9
      }

      // Find Jetty's ALPN extension for OpenJDK.
      try {
        val alpnClassName = "org.eclipse.jetty.alpn.ALPN"
        val alpnClass = Class.forName(alpnClassName, true, null)

   *     IOException}.
   */
  /*
   * The proper capitalization would be "swallowIoException." However:
   *
   * - It might be preferable to be consistent with the JDK precedent (which they stuck with even
   *   for "UncheckedIOException").
   *
   * - If we change the name, some of our callers break because our Android Lint ParameterName check

    // TODO(lukes): assert that the logs are full of errors
  }

  /**
   * Runs the corresponding {@link FuturesTest} test method in a new classloader that disallows
   * certain core JDK classes.
   */
  private void runTestMethod(ClassLoader classLoader) throws Exception {
    ClassLoader oldClassLoader = Thread.currentThread().getContextClassLoader();

   * application class loader.
   *
   * NOTE: The tests for this behavior (FinalizableReferenceQueueClassLoaderUnloadingTest) fail
   * strangely when run in JDK 9. We are considering this a known issue. Please see
   * https://github.com/google/guava/issues/3086 for more information.
   */

    // TODO(lukes): assert that the logs are full of errors
  }

  /**
   * Runs the corresponding {@link AbstractFutureTest} test method in a new classloader that
   * disallows certain core JDK classes.
   */
  private void runTestMethod(ClassLoader classLoader) throws Exception {
    ClassLoader oldClassLoader = Thread.currentThread().getContextClassLoader();

     * <p>
     * Note: This method no longer uses internal JDK APIs for safety and compatibility.
     * It now uses the standard String constructor.
     * </p>
     *
     * @param chars
     *            the char array
     * @return a new String, or null if the input is null
     * @deprecated This method originally used internal JDK APIs (sun.misc.SharedSecrets) for

## Setting up your development environment

In order to make changes to Gradle, you'll need:

* [Adoptium JDK](https://adoptium.net/temurin/archive/?version=17) (Java Development Kit) **version 17**. Fixed version is required to use [remote cache](#remote-build-cache).

    return new SingletonImmutableSet<>(e1);
  }

  /*
   * TODO: b/315526394 - Skip the Builder entirely for the of(...) methods, since we don't need to
   * worry that we might trigger the fallback to the JDK-backed implementation? (The varargs one
   * _could_, so we could keep it as it is. Or we could convince ourselves that hash flooding is
   * unlikely in practice there, too.)
   */

  /**