import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

import org.apache.maven.api.SessionData;
import org.apache.maven.api.services.MessageBuilderFactory;

         * unique within a single POM. Upon multiple declarations, 2.x just kept the last one but retained the order of
         * the first occurrence. So when we're in lenient/compat mode, we have to deal with such broken POMs and mimic
         * the way 2.x works. When we're in strict mode, the removal of duplicates just saves other merging steps from

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

import java.io.File;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;

import org.apache.maven.artifact.InvalidRepositoryException;
import org.apache.maven.bridge.MavenRepositorySystem;
import org.apache.maven.model.Dependency;
import org.apache.maven.model.Parent;

import java.nio.file.DirectoryNotEmptyException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.apache.maven.api.model.Model;
import org.apache.maven.api.services.Lookup;
import org.apache.maven.eventspy.EventSpy;

import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Properties;
import java.util.concurrent.Callable;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.BiConsumer;
import java.util.function.Supplier;
import java.util.function.UnaryOperator;
import java.util.stream.Collectors;

     *
     * <strong>Implementation note:</strong> while this method return type is {@link Map}, the
     * returned map instance implements {@link java.util.concurrent.ConcurrentMap} as well.
     *
     * @throws org.apache.maven.api.services.MavenException if not called from the within a mojo execution
     */
    @Nonnull

/**
 * <p>
 * A {@link Builder} encapsulates a strategy for building a set of Maven projects. The default strategy in Maven builds
 * the projects serially, but a {@link Builder} can employ any type of concurrency model to build the projects.
 */
@Named("singlethreaded")
@Singleton
public class SingleThreadedBuilder implements Builder {
    private final LifecycleModuleBuilder lifecycleModuleBuilder;

    @Inject

 * </p>
 * <strong>NOTE:</strong> This class is not part of any public api and can be changed or deleted without prior notice.
 *
 * @since 3.0
 */
// TODO From a concurrency perspective, this class is not good. The combination of mutable/immutable state is not nice
public class DependencyContext {

    private final MavenProject project;

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

import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.function.Supplier;

import org.apache.maven.api.services.ModelCache;
import org.apache.maven.api.services.Source;
import org.eclipse.aether.RepositoryCache;

 * under the License.
 */
package org.apache.maven.internal.impl.model;

import java.nio.file.Path;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Supplier;

import org.apache.maven.api.model.Model;
import org.apache.maven.api.services.ModelTransformerContext;
import org.apache.maven.api.services.model.*;

/**