} catch (SecurityException e) {
      generateCancellationCauses = false;
    }
    GENERATE_CANCELLATION_CAUSES = generateCancellationCauses;
  }

  /**
   * Tag interface marking trusted subclasses. This enables some optimizations. The implementation
   * of this interface must also be an AbstractFuture and must not override or expose for overriding
   * any of the public methods of ListenableFuture.
   */

   * @since 12.0
   */
  @GwtIncompatible // To be supported
  public static CacheBuilder<Object, Object> from(String spec) {
    return from(CacheBuilderSpec.parse(spec));
  }

  /**
   * Enables lenient parsing. Useful for tests and spec parsing.
   *
   * @return this {@code CacheBuilder} instance (for chaining)
   */
  @GwtIncompatible // To be supported
  @CanIgnoreReturnValue