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

    private RoleTypeDbm() {
    }

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

    private BoostDocumentRuleDbm() {
    }

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

    private DuplicateHostDbm() {
    }

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

    private UserInfoDbm() {
    }

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

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;
import javax.xml.stream.XMLStreamException;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

    }

    private ArtifactResolutionResult collect(ArtifactSpec a) throws ArtifactResolutionException {
        return artifactCollector.collect(
                Collections.singleton(a.artifact),
                projectArtifact.artifact,
                null,
                null,
                null,
                source,
                null,
                Collections.emptyList(),

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

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

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;

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

    private GroupDbm() {
    }

    }

    @Override
    public Map<String, Collection<Integer>> create(Object... elements) {
      ImmutableMap.Builder<String, Integer> builder = ImmutableMap.builder();
      // assumes that each set is a singleton or less (as is done for the samples)
      for (Object elem : elements) {
        @SuppressWarnings("unchecked") // safe by generator contract

      new ImmutableClassToInstanceMap<>(ImmutableMap.<Class<?>, Object>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;
  }

  /**