All of these operations will produce their own unique errors in the absence of
  a coordinated offline strategy. In addition, efforts to unite these failing
  behaviors behind a consistent user interface is much, much more difficult if
  the system can't tell whether it has access to the network required by these
  operations.

  Offline mode really means anticipating a lack of network connectivity, and as

AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

         * 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
         * aftereffects and bogus error messages.
         */

            of the {@code ${os.name}} Java property, such as {@code Windows XP}.
          </description>
        </field>
        <field>
          <name>family</name>
          <version>4.0.0+</version>
          <type>String</type>
          <description>
            The general family of the OS to be used to activate the profile, such as
            {@code windows} or {@code unix}.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Provides basic services to manage Maven plugins and their mojos. This component is kept general in its design such
 * that the plugins/mojos can be used in arbitrary contexts. In particular, the mojos can be used for ordinary build
 * plugins as well as special purpose plugins like reports.
 *
 * @since 3.0
 */
@Named

     */
    @Nonnull
    Map<String, String> getUserProperties();

    /**
     * Returns immutable system properties to use for interpolation. The system properties are collected from the
     * runtime environment such as {@link System#getProperties()} and environment variables
     * (prefixed with {@code env.}).
     *
     * @return the system properties, never {@code null}
     */
    @Nonnull

        } else {
            context.remove(key);
        }
    }

    /**
     * Returns context value of this project associated with the given key or null if this project has no such value.
     */
    public Object getContextValue(String key) {
        if (context == null) {
            return null;
        }
        return context.get(key);
    }

    /**

INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

package org.apache.maven.api;

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Immutable;
import org.apache.maven.api.annotations.Nonnull;

/**
 * An artifact points to a resource such as a jar file or war application.
 *
 * @since 4.0.0
 */
@Experimental
@Immutable
public interface Artifact {

    /**
     * Returns a unique identifier for this artifact.

            The important difference is this will not resolve the files for the dependencies, i.e. the artifacts
            associated with a Maven project can lack a file. As such, this annotation is meant for Mojos that only
            want to analyze the set of transitive dependencies, in particular during early lifecycle phases where