Because of that, it's now recommended to instead use the `lifespan` as explained above.

## Technical Details { #technical-details }

Just a technical detail for the curious nerds. 🤓

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 * Other contributors include Andrew Wright, Jeffrey Hayes,
 * Pat Fisher, Mike Judd.
 */

/*
 * Source:
 * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/test/tck/JSR166TestCase.java?revision=1.90

 * {@link Comparator#compare} instead of {@link Object#equals} to determine equivalence of
 * instances.
 *
 * <p><b>Warning:</b> The comparators or comparables used must be <i>consistent with equals</i> as
 * explained by the {@link Comparable} class specification. Otherwise, the resulting multiset will
 * violate the general contract of {@link SetMultimap}, which is specified in terms of {@link
 * Object#equals}.
 *

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

/*
 * Source:
 * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jsr166e/extra/AtomicDoubleArray.java?revision=1.5
 * (Modified to adapt to guava coding conventions and
 * to use AtomicLongArray instead of sun.misc.Unsafe)
 */

   * method directly.
   *
   * <p>The returned object is serializable if {@code comparator} is serializable.
   *
   * <p><b>Java 8+ users:</b> this class is now obsolete as explained in the class documentation, so
   * there is no need to use this method.
   *
   * @param comparator the comparator that defines the order

   * {@link #get} instead.
   *
   * @throws UncheckedExecutionException if an exception was thrown while loading the value. (As
   *     explained in the last paragraph above, this should be an unchecked exception only.)
   * @throws ExecutionError if an error was thrown while loading the value
   */
  @CanIgnoreReturnValue // TODO(b/27479612): consider removing this?

/*
 * Written by Doug Lea and Martin Buchholz with assistance from
 * members of JCP JSR-166 Expert Group and released to the public
 * domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

/*
 * Source:
 * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/test/tck-jsr166e/AtomicDoubleArrayTest.java?revision=1.13
 * (Modified to adapt to guava coding conventions)
 */

package com.google.common.util.concurrent;

   * {@link #get} instead.
   *
   * @throws UncheckedExecutionException if an exception was thrown while loading the value. (As
   *     explained in the last paragraph above, this should be an unchecked exception only.)
   * @throws ExecutionError if an error was thrown while loading the value
   */
  @CanIgnoreReturnValue // TODO(b/27479612): consider removing this?

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

/*
 * Source:
 * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jsr166e/Striped64.java?revision=1.9
 */

package com.google.common.cache;

import com.google.common.annotations.GwtIncompatible;
import java.lang.reflect.Field;

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 * Other contributors include Andrew Wright, Jeffrey Hayes,
 * Pat Fisher, Mike Judd.
 */

/*
 * Source:
 * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/test/tck/JSR166TestCase.java?revision=1.90