PluginExecution existing = merged.get(key);
                    if (existing != null) {
                        element = mergePluginExecution(existing, element, sourceDominant, context);
                    }
                    merged.put(key, element);
                }

                builder.executions(merged.values());
            }
        }

        @Override

            Map<String, String> merged = new HashMap<>();
            if (sourceDominant) {
                merged.putAll(target.getProperties());
                putAll(merged, source.getProperties(), CHILD_DIRECTORY_PROPERTY);
            } else {
                putAll(merged, source.getProperties(), CHILD_DIRECTORY_PROPERTY);
                merged.putAll(target.getProperties());
            }

                    if (dependency != null) {
                        Dependency merged = mergeDependency(dependency, managedDependency, false, context);
                        if (merged != dependency) {
                            dependencies.put(key, merged);
                            modified = true;
                        }
                    }
                }

                    PluginExecution existing = merged.get(key);
                    if (existing != null) {
                        element = mergePluginExecution(element, existing, sourceDominant, context);
                    }
                    merged.put(key, element);
                }

                builder.executions(merged.values());
            }
        }
    }

            metadata.storeInLocalRepository(localRepo, localRepo);
            merged = true;
        } catch (Exception e) {
            throw new RepositoryException(e.getMessage(), e);
        }
    }

    public boolean isMerged() {
        return merged;
    }

    public String getGroupId() {
        return emptify(metadata.getGroupId());
    }

        Metadata recessive = read(existing);

        merge(recessive);

        write(result, metadata);

        merged = true;
    }

    @Override
    public boolean isMerged() {
        return merged;
    }

    protected abstract void merge(Metadata recessive);

    static Metadata read(Path metadataPath) throws RepositoryException {

        Model source = Model.newBuilder().artifactId("SOURCE").build();

        Model merged = mavenMerger.merge(target, source, true, null);
        assertThat(merged.getArtifactId(), is("SOURCE"));

        merged = mavenMerger.merge(target, source, false, null);
        assertThat(merged.getArtifactId(), is("TARGET"));
    }

    @Test
    void mergeSameContributors() {
        Contributor contributor =

import java.util.ArrayList;
import java.util.List;

import org.apache.maven.building.Problem;
import org.apache.maven.toolchain.model.PersistedToolchains;

/**
 * Holds the result of the merged toolchains and holds the problems during this build, if any.
 *
 * @since 3.3.0
 * @deprecated since 4.0.0, use {@link org.apache.maven.api.services.ToolchainsBuilder} instead
 */
@Deprecated(since = "4.0.0")

    /**
     * Merges the specified source object into the given target object.
     *
     * @param target The target object whose existing contents should be merged with the source, must not be
     *            <code>null</code>.
     * @param source The (read-only) source object that should be merged into the target object, may be
     *            <code>null</code>.

    Iterator<C> merged =
        mergeSorted(
            transform(backingMap.values(), (Map<C, V> input) -> input.keySet().iterator()),
            comparator);

    return new AbstractIterator<C>() {
      @CheckForNull C lastValue;

      @Override
      @CheckForNull
      protected C computeNext() {
        while (merged.hasNext()) {
          C next = merged.next();