@VisibleForTesting long refreshDuration;
  @VisibleForTesting @CheckForNull TimeUnit refreshTimeUnit;
  /** Specification; used for toParseableString(). */
  private final String specification;

  private CacheBuilderSpec(String specification) {
    this.specification = specification;
  }

  /**
   * Creates a CacheBuilderSpec from a string.
   *
   * @param cacheBuilderSpecification the string form

   * @param key the value to be searched for.
   * @param comparator the comparator by which the list is ordered.
   * @param presentBehavior the specification for what to do if at least one element of the list
   *     compares as equal to the key.
   * @param absentBehavior the specification for what to do if no elements of the list compare as
   *     equal to the key.

 * equivalence of instances.
 *
 * <p><b>Warning:</b> The comparison must be <i>consistent with equals</i> as explained by the
 * {@link Comparable} class specification. Otherwise, the resulting multiset will violate the {@link
 * java.util.Collection} contract, which is specified in terms of {@link Object#equals}.
 *
 * <p>See the Guava User Guide article on <a href=

   * please comment on <a href="https://github.com/google/guava/issues/3086">issue 3086</a>.
   */
  private static boolean isJdk9OrHigher() {
    return JAVA_SPECIFICATION_VERSION.value().startsWith("9")
        || JAVA_SPECIFICATION_VERSION.value().startsWith("10");
  }

   * please comment on <a href="https://github.com/google/guava/issues/3086">issue 3086</a>.
   */
  private static boolean isJdk9OrHigher() {
    return JAVA_SPECIFICATION_VERSION.value().startsWith("9")
        || JAVA_SPECIFICATION_VERSION.value().startsWith("10");
  }

  }

  /**
   * Returns the absolute uri of the Class-Path entry value as specified in <a
   * href="http://docs.oracle.com/javase/8/docs/technotes/guides/jar/jar.html#Main_Attributes">JAR
   * File Specification</a>. Even though the specification only talks about relative urls, absolute
   * urls are actually supported too (for example, in Maven surefire plugin).
   */
  @VisibleForTesting

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.base.StandardSystemProperty.JAVA_SPECIFICATION_VERSION;
import static com.google.common.base.StandardSystemProperty.OS_NAME;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.util.concurrent.MoreExecutors.directExecutor;

   * {@code ExecutorService} imposes a small locking overhead on each task submission in order to
   * implement shutdown and termination behavior.
   *
   * <p>The implementation deviates from the {@code ExecutorService} specification with regards to
   * the {@code shutdownNow} method. First, "best-effort" with regards to canceling running tasks is
   * implemented as "no-effort". No interrupts or other attempts are made to stop threads executing

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.base.StandardSystemProperty.JAVA_SPECIFICATION_VERSION;
import static com.google.common.base.StandardSystemProperty.OS_NAME;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;

    }
    throw new NullPointerException("Both parameters are null");
  }

  /**
   * Creates an instance of {@link ToStringHelper}.
   *
   * <p>This is helpful for implementing {@link Object#toString()}. Specification by example:
   *
   * <pre>{@code
   * // Returns "ClassName{}"
   * MoreObjects.toStringHelper(this)
   *     .toString();
   *
   * // Returns "ClassName{x=1}"
   * MoreObjects.toStringHelper(this)