+ "plugin(s) that have goals not marked as thread-safe to support parallel execution.",
                        "While this /may/ work fine, please look for plugin updates and/or "
                                + "request plugins be made thread-safe.",
                        "If reporting an issue, report it against the plugin in question, not against Apache Maven.")) {

 * abused as a cache (i.e. for storing values that can be re-calculated) to avoid memory exhaustion.
 * <p>
 * <strong>Note:</strong> Actual implementations must be thread-safe.
 *
 * @see Session#getData()
 * @since 4.0.0
 */
@Experimental
@ThreadSafe
@Provider
public interface SessionData {

    /**
     * Associates the specified session data with the given key.
     *

                    }
                }
            }
        }
        return plugins.values();
    }

    private PluginInfo extractPluginInfo(Artifact artifact) {
        // sanity: jar, no classifier and file exists
        if (artifact != null
                && "jar".equals(artifact.getExtension())
                && "".equals(artifact.getClassifier())
                && artifact.getPath() != null) {

        </field>
        <field>
          <name>threadSafe</name>
          <version>1.0.0/1.1.0</version>
          <type>boolean</type>
          <description>
            Marks this Mojo as being thread-safe, i.e. the Mojo safely supports concurrent execution during parallel
            builds. Mojos without this annotation will make Maven output a warning when used during a parallel build
            session.
            @since Maven 3.0.

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

import java.util.HashMap;
import java.util.Map;

/**
 * Type safe enumeration for the artifact status field.
 *
 */
@Deprecated
public final class ArtifactStatus implements Comparable<ArtifactStatus> {
    /**
     * No trust - no information about status.
     */

        }
    }

    // ===================================================================================================
    /**
     * Helper class to traverse graph. Required to make the containing method thread-safe
     * and yet use class level data to lessen stack usage in recursion
     */
    private class ClasspathGraphVisitor {
        MetadataGraph graph;

        ClasspathContainer cpc;

public class SystemProperties {
    /**
     * Thread-safe System.properties copy implementation.
     */
    public static void addSystemProperties(Properties props) {
        props.putAll(getSystemProperties());
    }

    /**
     * Returns a copy of {@link System#getProperties()} in a thread-safe manner.
     *
     * @return {@link System#getProperties()} obtained in a thread-safe manner.
     */

                if (vertex != null) {
                    addEdge(projectVertex, vertex, project, projectMap, force, safe);
                }
            } else {
                for (Vertex vertex : vertices.values()) {
                    addEdge(projectVertex, vertex, project, projectMap, force, safe);
                }
            }
        }
    }

    private void addEdge(
            Vertex fromVertex,

    private volatile ProjectSegment currentBuild;

    private final PrintStream originalSystemOUtStream;

    private final ConsolePrinter printer;

    /**
     * A simple but safe solution for printing to the console.
     */
    class ConsolePrinter implements Runnable {
        private volatile boolean running;

        private final ProjectBuildList projectBuildList;

        msgs.add("* as @threadSafe to support parallel building.                  *");
        msgs.add("* While this /may/ work fine, please look for plugin updates    *");
        msgs.add("* and/or request plugins be made thread-safe.                   *");
        msgs.add("* If reporting an issue, report it against the plugin in        *");
        msgs.add("* question, not against maven-core                              *");