new TestStringSetGenerator() {
              @Override
              public Set<String> create(String[] elements) {
                return singleton(elements[0]);
              }
            })
        .named("singleton")
        .withFeatures(
            CollectionFeature.SERIALIZABLE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionSize.ONE)

<components namespace="fessCrawler">
	<include path="crawler/container.xml" />

	<component name="contentLengthHelper"
		class="org.codelibs.fess.crawler.helper.ContentLengthHelper" instance="singleton">
	</component>

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.model.normalization;

import javax.inject.Named;
import javax.inject.Singleton;

import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.apache.maven.model.Build;

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.lifecycle.internal;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.time.Duration;
import java.time.Instant;
import java.util.HashSet;
import java.util.List;

import org.apache.maven.api.MonotonicClock;
import org.apache.maven.execution.BuildSuccess;

            this.destroyed = true;
        }

        public static void resetCounter() {
            instanceCounter.set(0);
        }
    }

    /**
     * Singleton test component for testing singleton behavior
     */
    public static class SingletonTestComponent {
        private static int instanceCount = 0;

        public SingletonTestComponent() {
            instanceCount++;

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.execution;

import javax.inject.Named;
import javax.inject.Singleton;

import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Properties;

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.repository.internal;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.io.InputStream;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;

<components namespace="fessCrawler">
	<include path="crawler/container.xml" />

	<component name="mimeTypeHelper"
		class="org.codelibs.fess.crawler.helper.impl.MimeTypeHelperImpl" instance="singleton">
	</component>

	"http://dbflute.org/meta/lastadi10.dtd">
<components namespace="fessCrawler">
	<include path="crawler/container.xml" />

	<component name="sitemapsHelper" class="org.codelibs.fess.crawler.helper.SitemapsHelper"
		instance="singleton">
	</component>

import static com.google.common.collect.testing.Helpers.testComparator;
import static java.util.Arrays.asList;
import static java.util.Collections.emptyIterator;
import static java.util.Collections.singleton;

import com.google.common.annotations.GwtCompatible;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;