setImplementation(Deque.class, ArrayDeque.class);
    setImplementation(OutputStream.class, ByteArrayOutputStream.class);
    setImplementation(PrintStream.class, Dummies.InMemoryPrintStream.class);
    setImplementation(PrintWriter.class, Dummies.InMemoryPrintWriter.class);
    setImplementation(Queue.class, ArrayDeque.class);
    setImplementation(Random.class, Dummies.DeterministicRandom.class);
    setImplementation(

    setImplementation(Deque.class, ArrayDeque.class);
    setImplementation(OutputStream.class, ByteArrayOutputStream.class);
    setImplementation(PrintStream.class, Dummies.InMemoryPrintStream.class);
    setImplementation(PrintWriter.class, Dummies.InMemoryPrintWriter.class);
    setImplementation(Queue.class, ArrayDeque.class);
    setImplementation(Random.class, Dummies.DeterministicRandom.class);
    setImplementation(

        MojoDescriptor mojo = new MojoDescriptor();
        mojo.setPluginDescriptor(pluginDescriptor);

        mojo.setGoal(c.getChild("goal").getValue());

        mojo.setImplementation(c.getChild("implementation").getValue());

        PlexusConfiguration langConfig = c.getChild("language");

        if (langConfig != null) {
            mojo.setLanguage(langConfig.getValue());
        }

            this.registration = registration;
        }

        @Override
        public TypeRegistrationBuilder<S> withImplementation(ModelType<?> implementationType) {
            registration.setImplementation(implementationType, source);
            return this;
        }

        @Override
        public TypeRegistrationBuilder<S> withInternalView(ModelType<?> internalView) {

        this.setOnlineRequired(md.isOnlineRequired());
        this.setProjectRequired(md.isProjectRequired());
        this.setSince(md.getSince());
        this.setThreadSafe(true);
        this.setImplementation(md.getImplementation());
        try {
            this.setParameters(md.getParameters().stream().map(Parameter::new).collect(Collectors.toList()));
        } catch (DuplicateParameterException e) {

    @Inject
    public DefaultToolchainSpec() {
        getVendor().convention(getConventionVendor());
        getImplementation().convention(getConventionImplementation());
    }
    @Override
    public JavaToolchainSpecInternal.Key toKey() {
        return new Key(getLanguageVersion().getOrNull(), getVendor().getOrNull(), getImplementation().getOrNull());
    }

    @Override
    public boolean isConfigured() {

// end::custom-dependencies-type[]

// tag::custom-dependencies-scopes[]
    /**
     * Dependency scope called "implementation"
     */
    DependencyCollector getImplementation();
// end::custom-dependencies-scopes[]

        ClassImplementationSnapshot currentImplementation = Cast.uncheckedNonnullCast(thisExecution.getImplementation());
        ClassImplementationSnapshot previousImplementation = Cast.uncheckedNonnullCast(lastExecution.getImplementation());
        ImmutableList<ImplementationSnapshot> currentAdditionalImplementations = Cast.uncheckedNonnullCast(thisExecution.getAdditionalImplementations());

// tag::wire-dependencies[]
        project.getConfigurations().dependencyScope("exampleImplementation", conf -> {
            conf.fromDependencyCollector(example.getDependencies().getImplementation());
        });
// end::wire-dependencies[]
    }

        def spec = TestUtil.objectFactory().newInstance(DefaultToolchainSpec)
        spec.getLanguageVersion().set(JavaLanguageVersion.of(javaVersion.getMajorVersion()))
        spec.getVendor().set(vendor)
        spec.getImplementation().set(implementation)

        then:
        new JvmInstallationMetadataMatcher(spec).test(metadata)

        where: