return getExecutionPlanItems().iterator();
    }

    /**
     * Returns the last ExecutionPlanItem in the supplied phase. If no items are in the specified phase,
     * the closest executionPlanItem from an earlier phase item will be returned.
     *
     * @param requestedPhase the requested phase
     *                       The execution plan item
     * @return The ExecutionPlanItem or null if none can be found
     */

            // Check if the project is part of the session (not filtered by -pl, -rf, etc). If so, we check
            // if a possible earlier Maven invocation produced some output for that project which we can use.
            boolean projectHasOutputFromPreviousSession =
                    !session.getProjects().contains(project) && outputDirectory.exists();

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

/**
 * Describes a problem that was encountered during settings building. A problem can either be an exception that was
 * thrown or a simple string message. In addition, a problem carries a hint about its source, e.g. the settings file
 * that exhibits the problem.
 */
class DefaultBuilderProblem implements BuilderProblem {
    final String source;
    final int lineNumber;
    final int columnNumber;

 */
package org.apache.maven.building;

/**
 * Describes a problem that was encountered during settings building. A problem can either be an exception that was
 * thrown or a simple string message. In addition, a problem carries a hint about its source, e.g. the settings file
 * that exhibits the problem.
 *
 */
class DefaultProblem implements Problem {

    private final String source;

    private final int lineNumber;

 *
 * @since 4.0.0
 */
@Experimental
@Consumer
public interface PropertyContributor extends SpiService {
    /**
     * Invoked just before session is created with a mutable map that carries collected user properties so far.
     *
     * @param userProperties The mutable user properties, never {@code null}.
     */
    void contribute(Map<String, String> userProperties);

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

/**
 * Describes a problem that was encountered during model building. A problem can either be an exception that was thrown
 * or a simple string message. In addition, a problem carries a hint about its source, e.g. the POM file that exhibits
 * the problem.
 *
 */
public class DefaultModelProblem implements ModelProblem {

    private final String source;

    private final int lineNumber;

        // We only check for groupId/artifactId/version/classifier cause if there is another
        // module with the same groupId/artifactId/version/classifier this will fail the build
        // earlier like "Project '...' is duplicated in the reactor.
        // So it is sufficient to check only groupId/artifactId/version/classifier and not the
        // packaging type.
        for (Dependency dependency : dependencies) {

 */
package org.apache.maven.api.services;

/**
 * Describes a problem that was encountered during model building. A problem can either be an exception that was thrown
 * or a simple string message. In addition, a problem carries a hint about its source, e.g. the POM file that exhibits
 * the problem.
 *
 */
public interface ModelProblem extends BuilderProblem {

    /**
     * Version
     */
    enum Version {