*
     * @param request The execution request to populate, must not be {@code null}.
     * @param toolchains The toolchains to copy into the execution request, may be {@code null}.
     * @return The populated execution request, never {@code null}.
     * @throws MavenExecutionRequestPopulationException If the execution request could not be populated.
     * @since 3.3.0
     */

h3. Discovery all Plexus components

Once the ClassRealm is populated with the plugin artifact and its dependency artifacts a discovery operation must be performed on the plugin ClassRealm in order to discover any Plexus components that may be present in any of the artifacts required for the plugins execution.

h3. Looking up the plugin with a configuration

        /*
         * This provides backward-compat with 2.x that allowed plugins like the maven-remote-resources-plugin:1.0 to
         * populate the builder configuration with model repositories instead of artifact repositories.
         */

        if (repositories != null) {
            boolean normalized = false;

import org.apache.maven.api.services.DependencyResolverResult;

/**
 * The result of collecting dependencies with a dependency resolver.
 * New instances are initially empty. Callers must populate with calls
 * to the following methods, in that order:
 *
 * <ul>
 *   <li>{@link #addOutputDirectory(Path, Path, PathModularizationCache)} (optional)</li>

        try {
            return expressionEvaluator.evaluate(strValue) != null;
        } catch (ExpressionEvaluationException e) {
            // not important
            // will be reported during Mojo fields populate
        }

        // fallback - in case of error in expressionEvaluator
        return false;
    }

    @Override
    public final void validate(
            MavenSession mavenSession,

        // use DefaultJavaToolChain for compatibility with maven 3.2.3 and earlier

        @SuppressWarnings("deprecation")
        JavaToolchainImpl jtc = new DefaultJavaToolChain(model, logger);

        // populate the provides section
        Properties provides = model.getProvides();
        for (Entry<Object, Object> provide : provides.entrySet()) {
            String key = (String) provide.getKey();

 -----
 Maven plugins
 -----
 The Maven Team
 -----

Maven plugin execution isolation

 Maven2 takes advantage of Plexus' ability to execute a component using a
 ClassWorlds ClassRealm that is populated with the JAR containing the
 component in question and all of its dependencies. Using ClassWorlds
 notation for realms we have the following:

+-----+
      [plexus.core]
            ^
            |

        this.lifecycleMap =
                Collections.unmodifiableMap(lifecycles.stream().collect(toMap(Lifecycle::getId, identity())));
    }

    /**
     * Plexus: Populates the lifecycle map from the injected list of lifecycle mappings (if not already done).
     */
    private synchronized void initLifecycleMap() {
        if (lifecycleMap == null) {
            lifecycleMap = new HashMap<>();

            MavenProject project, Plugin plugin, RepositorySystemSession session) throws PluginManagerException;

    /**
     * Looks up the mojo for the specified mojo execution and populates its parameters from the configuration given by
     * the mojo execution. The mojo/plugin descriptor associated with the mojo execution provides the class realm to

    // it's all encapsulated here so it appears normalized to the POM builder.

    // We are going to take the project packaging and find all plugin in the default lifecycle and create
    // fully populated Plugin objects, including executions with goals and default configuration taken
    // from the plugin.xml inside a plugin.
    //