firstException = expected;
    // Second time should also fail, with a cached causal chain.
    expected = assertThrows(PotentialDeadlockException.class, () -> lockA.lock());
    checkMessage(expected, "LockB -> LockA", "LockA -> LockB");
    // The causal chain should be cached.
    assertSame(firstException.getCause(), expected.getCause());
    // lockA should work after lockB is released.

   * part of the smeared hash of the element not covered by the hashtable mask, whereas the low bits
   * are the "next" pointer (pointing to the next entry in the bucket chain), which will always be
   * less than or equal to the hashtable mask.
   *
   * <pre>
   * hash  = aaaaaaaa
   * mask  = 00000fff
   * next  = 00000bbb
   * entry = aaaaabbb
   * </pre>
   *

   * part of the smeared hash of the key not covered by the hashtable mask, whereas the low bits are
   * the "next" pointer (pointing to the next entry in the bucket chain), which will always be less
   * than or equal to the hashtable mask.
   *
   * <pre>
   * hash  = aaaaaaaa
   * mask  = 00000fff
   * next  = 00000bbb
   * entry = aaaaabbb
   * </pre>
   *

      // held
      chain = segment.newEntry(key, cache.hash(key), chain);
      if (i == 0) {
        head = chain;
      }
    }
  }

  @SuppressWarnings("GuardedBy")
  @Benchmark
  int time(int reps) {
    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      // TODO(b/145386688): This access should be guarded by 'this.segment', which is not currently

   * already been determined.
   */
  public abstract <T extends @Nullable Object> ComparisonChain compare(
      @ParametricNullness T left, @ParametricNullness T right, Comparator<T> comparator);

  /**
   * Compares two {@code int} values as specified by {@link Ints#compare}, <i>if</i> the result of
   * this comparison chain has not already been determined.
   */

  }

  /**
   * Gets a {@code Throwable} cause chain as a list. The first entry in the list will be {@code
   * throwable} followed by its cause hierarchy. Note that this is a snapshot of the cause chain and
   * will not reflect any subsequent changes to the cause chain.
   *
   * <p>Here's an example of how it can be used to find specific types of exceptions in the cause
   * chain:
   *
   * <pre>

  }

  /**
   * Gets a {@code Throwable} cause chain as a list. The first entry in the list will be {@code
   * throwable} followed by its cause hierarchy. Note that this is a snapshot of the cause chain and
   * will not reflect any subsequent changes to the cause chain.
   *
   * <p>Here's an example of how it can be used to find specific types of exceptions in the cause
   * chain:
   *
   * <pre>

  public void testFutureGetThrowsRuntimeException() throws Exception {
    BadFuture badInput = new BadFuture(Futures.immediateFuture(20));
    ListenableFuture<String> chain = buildChainingFuture(badInput);
    ExecutionException e = assertThrows(ExecutionException.class, () -> chain.get());
    assertSame(RuntimeException.class, e.getCause().getClass());
  }

  /** Proxy to throw a {@link RuntimeException} out of the {@link #get()} method. */

          break;
        }
      }
    }
  }

  /**
   * Represents a detected cycle in lock acquisition ordering. The exception includes a causal chain
   * of {@code ExampleStackTrace} instances to illustrate the cycle, e.g.
   *
   * <pre>
   * com....PotentialDeadlockException: Potential Deadlock from LockC -&gt; ReadWriteA
   *   at ...
   *   at ...

    InternalEntry<Object, Object, ?> entry = null;
    for (int i = 0; i < originalCount; i++) {
      Object key = new Object();
      Object value = new Object();
      int hash = map.hash(key);
      // chain all entries together as we only have a single bucket
      entry = segment.newEntryForTesting(key, hash, entry);
      segment.setValueForTesting(entry, value);
    }
    segment.setTableEntryForTesting(0, entry);