private void shallowMerge(
            List<ToolchainModel> dominant, List<ToolchainModel> recessive, String recessiveSourceLevel) {
        Map<Object, ToolchainModel> merged = new LinkedHashMap<>();

        for (ToolchainModel dominantModel : dominant) {
            Object key = getToolchainModelKey(dominantModel);

            merged.put(key, dominantModel);
        }

        for (ToolchainModel recessiveModel : recessive) {

import org.apache.maven.api.Toolchain;
import org.apache.maven.api.annotations.Consumer;
import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.toolchain.ToolchainModel;

/**
 * Factory interface for creating toolchain instances from configuration models.
 *
 * <p>This factory is responsible for instantiating concrete toolchain implementations

    @Test
    void testModelAndFactory() {
        MavenSession session = mock(MavenSession.class);
        List<ToolchainModel> toolchainModels = List.of(
                ToolchainModel.newBuilder().type("basic").build(),
                ToolchainModel.newBuilder().type("basic").build(),
                ToolchainModel.newBuilder().type("rare").build());
        Session sessionv4 = mock(Session.class);

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

import org.apache.maven.toolchain.model.ToolchainModel;
import org.slf4j.Logger;

/**
 * Provides backwards compatibility with Maven 3.2.3 and earlier. Clients that do not require compatibility with Maven
 * 3.2.3 and earlier are encouraged to use {@link JavaToolchainImpl}.

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

import org.apache.maven.toolchain.model.ToolchainModel;

/**
 * Internal toolchain factory, to prepare toolchains instances.
 *
 * @since 2.0.9
 * @deprecated Use {@link org.apache.maven.api.services.ToolchainFactory} instead.
 */
@Deprecated(since = "4.0.0")

    }

    @Nonnull
    @Override
    public Collection<ToolchainModel> getToolchains() {
        return getMavenSession().getRequest().getToolchains().values().stream()
                .flatMap(Collection::stream)
                .map(org.apache.maven.toolchain.model.ToolchainModel::getDelegate)
                .toList();
    }

    @Nonnull
    @Override

            throws MavenExecutionRequestPopulationException {
        if (toolchains != null) {
            Map<String, List<ToolchainModel>> groupedToolchains = new HashMap<>(2);

            for (ToolchainModel model : toolchains.getToolchains()) {
                if (!groupedToolchains.containsKey(model.getType())) {
                    groupedToolchains.put(model.getType(), new ArrayList<>());

import org.apache.maven.toolchain.RequirementMatcherFactory;
import org.apache.maven.toolchain.ToolchainFactory;
import org.apache.maven.toolchain.ToolchainPrivate;
import org.apache.maven.toolchain.model.ToolchainModel;
import org.codehaus.plexus.util.xml.Xpp3Dom;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * JDK toolchain factory.
 * This is a <code>ToolchainFactory</code> Plexus component registered with

                public org.apache.maven.api.Toolchain createToolchain(
                        @Nonnull org.apache.maven.api.toolchain.ToolchainModel model) throws ToolchainFactoryException {
                    try {
                        return getToolchainV4(v3Factory.createToolchain(new ToolchainModel(model)));
                    } catch (MisconfiguredToolchainException e) {
                        throw new RuntimeException(e);

              <!--              <exclude>org.apache.maven.toolchain.merge.MavenToolchainMerger#mergeToolchainModelConfiguration(org.apache.maven.toolchain.model.ToolchainModel,org.apache.maven.toolchain.model.ToolchainModel):METHOD_REMOVED</exclude>-->
            </excludes>
          </parameter>