String canonical = "a";
    String not = new String("a");

    Interner<String> pool = Interners.newWeakInterner();
    assertSame(canonical, pool.intern(canonical));
    assertSame(canonical, pool.intern(not));
  }

  public void testWeak_null() {
    Interner<String> pool = Interners.newWeakInterner();
    assertThrows(NullPointerException.class, () -> pool.intern(null));
  }

  public void testWeak_builder() {

    String canonical = "a";
    String not = new String("a");

    Interner<String> pool = Interners.newWeakInterner();
    assertSame(canonical, pool.intern(canonical));
    assertSame(canonical, pool.intern(not));
  }

  public void testWeak_null() {
    Interner<String> pool = Interners.newWeakInterner();
    assertThrows(NullPointerException.class, () -> pool.intern(null));
  }

  public void testWeak_builder() {

 * are available from the {@link Interners} class.
 *
 * <p>Note that {@code String.intern()} has some well-known performance limitations, and should
 * generally be avoided. Prefer {@link Interners#newWeakInterner} or another {@code Interner}
 * implementation even for {@code String} interning.
 *
 * @author Kevin Bourrillion
 * @since 3.0
 */
@DoNotMock("Use Interners.new*Interner")
@J2ktIncompatible
@GwtIncompatible

 *
 * @author Dimitris Andreou
 */
@NullUnmarked
public class InternersBenchmark {
  @CanIgnoreReturnValue
  @Benchmark
  int weakInterner(int reps) {
    Interner<String> interner = Interners.newWeakInterner();
    for (int i = 0; i < reps; i++) {
      String unused = interner.intern(Double.toHexString(Math.random()));
    }
    return reps;
  }

  @CanIgnoreReturnValue
  @Benchmark

 * are available from the {@link Interners} class.
 *
 * <p>Note that {@code String.intern()} has some well-known performance limitations, and should
 * generally be avoided. Prefer {@link Interners#newWeakInterner} or another {@code Interner}
 * implementation even for {@code String} interning.
 *
 * @author Kevin Bourrillion
 * @since 3.0
 */
@DoNotMock("Use Interners.new*Interner")
@J2ktIncompatible
@GwtIncompatible

  }

  public enum InternerImpl implements InternerImplEnum {
    WeakInternerImpl {
      @Override
      public <E> Interner<E> create(Collection<E> contents) {
        Interner<E> interner = Interners.newWeakInterner();
        for (E e : contents) {
          E unused = interner.intern(e);
        }
        return interner;
      }
    },
    StrongInternerImpl {
      @Override