this.closed = false;
        }

        boolean isAlive() {
            return resourceRef.get() != null && !closed;
        }

        long getAge() {
            return System.currentTimeMillis() - creationTime;
        }
    }

    private ResourceManager() {
        ThreadFactory threadFactory = r -> {

/**
 * Since annotations have some reusability issues that force copy and paste all over the place, it's
 * worth having a test to ensure that all our Feature enums have their annotations correctly set up.
 *
 * @author George van den Driessche
 */
public class FeatureEnumTest extends TestCase {
  private static void assertGoodTesterAnnotation(Class<? extends Annotation> annotationClass) {
    assertNotNull(

import java.util.List;
import java.util.Set;
import junit.framework.TestSuite;

/**
 * Creates, based on your criteria, a JUnit test suite that exhaustively tests a Set implementation.
 *
 * @author George van den Driessche
 */
@GwtIncompatible
public class SetTestSuiteBuilder<E>
    extends AbstractCollectionTestSuiteBuilder<SetTestSuiteBuilder<E>, E> {

/**
 * Since annotations have some reusability issues that force copy and paste all over the place, it's
 * worth having a test to ensure that all our Feature enums have their annotations correctly set up.
 *
 * @author George van den Driessche
 */
public class FeatureEnumTest extends TestCase {
  private static void assertGoodTesterAnnotation(Class<? extends Annotation> annotationClass) {
    assertNotNull(

import com.google.common.annotations.J2ktIncompatible;
import java.lang.reflect.Method;
import org.junit.Ignore;

/**
 * Tests {@link java.util.List#hashCode}.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

import com.google.common.collect.testing.features.CollectionSize;
import java.lang.reflect.Method;
import java.util.Collection;
import org.junit.Ignore;

/**
 * Tests {@link java.util.Set#hashCode}.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

import java.util.List;
import java.util.Set;
import junit.framework.TestSuite;

/**
 * Creates, based on your criteria, a JUnit test suite that exhaustively tests a List
 * implementation.
 *
 * @author George van den Driessche
 */
@GwtIncompatible
public final class ListTestSuiteBuilder<E>
    extends AbstractCollectionTestSuiteBuilder<ListTestSuiteBuilder<E>, E> {

import com.google.common.annotations.J2ktIncompatible;
import java.lang.reflect.Method;
import org.junit.Ignore;

/**
 * Tests {@link java.util.List#hashCode}.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

 * @param <G> the type of the test generator required by this tester. An instance of G should
 *     somehow provide an instance of the class under test, plus any other information required to
 *     parameterize the test.
 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked
public class AbstractTester<G> extends TestCase {
  private G subjectGenerator;
  private String suiteName;
  private @Nullable Runnable setUp;

import java.util.Collection;
import java.util.Map;
import org.jspecify.annotations.NullMarked;

/**
 * Test {@link Multimap#asMap()} for an arbitrary multimap with {@link MapInterfaceTest}.
 *
 * @author George van den Driessche
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public abstract class AbstractMultimapAsMapImplementsMapTest
    extends MapInterfaceTest<String, Collection<Integer>> {