// ===================================================================================
    //                                                                           Singleton
    //                                                                           =========
    private static final RelatedContentDbm _instance = new RelatedContentDbm();

    private RelatedContentDbm() {
    }

    // ===================================================================================
    //                                                                           Singleton
    //                                                                           =========
    private static final BadWordDbm _instance = new BadWordDbm();

    private BadWordDbm() {
    }

    // ===================================================================================
    //                                                                           Singleton
    //                                                                           =========
    private static final BoostDocumentRuleDbm _instance = new BoostDocumentRuleDbm();

    private BoostDocumentRuleDbm() {
    }

 * 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 javax.xml.stream.XMLStreamException;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;

    // ===================================================================================
    //                                                                           Singleton
    //                                                                           =========
    private static final ScheduledJobDbm _instance = new ScheduledJobDbm();

    private ScheduledJobDbm() {
    }

     * @return the merged XML node, or null if both inputs are null
     */
    protected abstract XmlNode doMerge(XmlNode dominant, XmlNode recessive, Boolean childMergeOverride);

    /**
     * Gets the singleton instance of the XmlService.
     *
     * @return the XmlService instance
     * @throws IllegalStateException if no implementation is found
     */
    private static XmlService getService() {

 * specific language governing permissions and limitations
 * under the License.
 */
package org.eclipse.sisu.plexus;

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

import java.io.StringReader;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;

    // ===================================================================================
    //                                                                           Singleton
    //                                                                           =========
    private static final JobLogDbm _instance = new JobLogDbm();

    private JobLogDbm() {
    }

      new ImmutableClassToInstanceMap<>(ImmutableMap.of());

  /**
   * Returns an empty {@code ImmutableClassToInstanceMap}.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   *
   * @since 19.0
   */
  @SuppressWarnings("unchecked")
  public static <B> ImmutableClassToInstanceMap<B> of() {
    return (ImmutableClassToInstanceMap<B>) EMPTY;
  }

  /**

import org.apache.maven.api.Lifecycle;
import org.apache.maven.api.cli.mvnup.UpgradeOptions;
import org.apache.maven.api.di.Named;
import org.apache.maven.api.di.Priority;
import org.apache.maven.api.di.Singleton;
import org.apache.maven.cling.invoker.mvnup.UpgradeContext;

import static eu.maveniverse.domtrip.maven.MavenPomElements.Elements.BUILD;
import static eu.maveniverse.domtrip.maven.MavenPomElements.Elements.EXECUTIONS;