if (isJava8()) {
      checkHelperVersion(getClass().getClassLoader(), "UnsafeAtomicHelper");
    } else {
      checkHelperVersion(getClass().getClassLoader(), "VarHandleAtomicHelper");
    }
    checkHelperVersion(NO_VAR_HANDLE, "UnsafeAtomicHelper");
    checkHelperVersion(NO_UNSAFE, "AtomicReferenceFieldUpdaterAtomicHelper");

  static {
    AtomicHelper helper;
    Throwable thrownUnsafeFailure = null;
    Throwable thrownAtomicReferenceFieldUpdaterFailure = null;

    if (mightBeAndroid()) {
      try {
        helper = new UnsafeAtomicHelper();
      } catch (Exception | Error unsafeFailure) { // sneaky checked exception
        thrownUnsafeFailure = unsafeFailure;

     */

    /*
     * We don't test UnsafeAtomicHelper here, since guava-android doesn't provide a way to use it
     * under the JVM. (We could arrange for one if we really wanted, but that will break once the
     * JDK further restricts access to Unsafe.) But we have coverage under an Android emulator,
     * which uses UnsafeAtomicHelper when it runs AbstractFutureTest itself.
     */

    Throwable thrownAtomicReferenceFieldUpdaterFailure = null;

    helper = VarHandleAtomicHelperMaker.INSTANCE.tryMakeVarHandleAtomicHelper();
    if (helper == null) {
      try {
        helper = new UnsafeAtomicHelper();
      } catch (Exception | Error unsafeFailure) { // sneaky checked exception
        thrownUnsafeFailure = unsafeFailure;

public class AbstractFutureDefaultAtomicHelperTest extends TestCase {
  public void testUsingExpectedAtomicHelper() throws Exception {
    if (isAndroid()) {
      assertThat(AbstractFutureState.atomicHelperTypeForTest()).isEqualTo("UnsafeAtomicHelper");
    } else {
      assertThat(AbstractFutureState.atomicHelperTypeForTest())
          .isEqualTo("AtomicReferenceFieldUpdaterAtomicHelper");
    }
  }

  private static boolean isJava8() {