private List<File> filesToDelete = new ArrayList<>();

    private final String baseFilename;

    private final String fileSuffix;

    private StackTraceElement callerInfo;

    private Thread cleanupWarning;

    private boolean warnAboutCleanup = false;

    public TestFileManager(String baseFilename, String fileSuffix) {
        this.baseFilename = baseFilename;
        this.fileSuffix = fileSuffix;

 * 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.

            }
        };
        injector.bindInstance(Injector.class, injector);
        bind(Injector.class).toInstance(injector);
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        if (classLoader == null) {
            classLoader = getClass().getClassLoader();
        }
        try {
            for (Iterator<URL> it = classLoader

        }
    }

    // ===================================================================================================
    /**
     * 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;

    }

    protected static File getFileForClasspathResource(String resource)
            throws FileNotFoundException, URISyntaxException {
        ClassLoader cloader = Thread.currentThread().getContextClassLoader();

        URL resourceUrl = cloader.getResource(resource);

        if (resourceUrl == null) {
            throw new FileNotFoundException("Unable to find: " + resource);
        }

        defaultLegacySupport.setSession(m1);

        MyRunnable myRunnable = new MyRunnable();
        Thread thread = new Thread(myRunnable);
        thread.start();

        MavenSession m2 = new MavenSession(null, null, mavenExecutionRequest, null);
        defaultLegacySupport.setSession(m2);
        latch.countDown();
        thread.join();
        assertNull(myRunnable.getSession());
    }

    class MyRunnable implements Runnable {

 */
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.
     */

        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                              *");

            }
            if (t instanceof Error) {
                throw (Error) t;
            }
        } finally {
            session.setCurrentProject(null);

            Thread.currentThread().setContextClassLoader(reactorContext.getOriginalContextClassLoader());
        }
    }

        if (metadataFile.length() == 0) {
            if (!metadataFile.delete()) {
                // sleep for 10ms just in case this is windows holding a file lock
                try {
                    Thread.sleep(10);
                } catch (InterruptedException e) {
                    // ignore
                }
                metadataFile.delete(); // if this fails, forget about it, we'll try to overwrite it anyway so no need