}

    /**
     * Creates and returns a new instance of {@link HashMap}.
     *
     * @param <K> the key type of {@link HashMap}
     * @param <V> the value type of {@link HashMap}
     * @return a new instance of {@link HashMap}
     * @see HashMap#HashMap()
     */
    public static <K, V> HashMap<K, V> newHashMap() {
        return new HashMap<>();
    }

    /**

    Map<@Nullable String, String> hashmap = new HashMap<>();
    hashmap.put("foo", "bar");
    hashmap.put(null, "baz");

    assertThat(Maps.toStringImpl(hashmap)).isEqualTo(hashmap.toString());
  }

  public void testToStringImplWithNullValues() throws Exception {
    Map<String, @Nullable String> hashmap = new HashMap<>();
    hashmap.put("foo", "bar");
    hashmap.put("baz", null);

        final List<Map<String, Object>> documents = new ArrayList<>();
        final Map<String, Object> doc1 = new HashMap<>();
        doc1.put("title", "Doc 1");
        doc1.put("content", "<h1>Title</h1><p>Content 1</p>");
        documents.add(doc1);

        final Map<String, Object> doc2 = new HashMap<>();
        doc2.put("title", "Doc 2");
        doc2.put("content", "<ul><li>Item A</li><li>Item B</li></ul>");

import java.io.PrintWriter;
import java.io.StringWriter;
import java.net.URLDecoder;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.UUID;
import java.util.function.Supplier;

import org.apache.commons.lang3.ArrayUtils;

import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.UncheckedExecutionException;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CountDownLatch;

    protected boolean useGoogleOffOn = true;

    /** Map storing field pruning rules */
    protected Map<String, Boolean> fieldPrunedRuleMap = new HashMap<>();

    /** Cache for storing parsed pruned tags by configuration ID */
    protected Map<String, PrunedTag[]> prunedTagsCache = new HashMap<>();

    /**
     * Default constructor.
     */
    public FessXpathTransformer() {
        super();
    }

    /**

import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.UncheckedExecutionException;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CountDownLatch;

    /** Initial facet parameter mappings */
    protected final Map<String, String> initFacetParamMap = new HashMap<>();

    /** Initial geographic parameter mappings */
    protected final Map<String, String> initGeoParamMap = new HashMap<>();

    /** List of facet query views */
    protected final List<FacetQueryView> facetQueryViewList = new ArrayList<>();

                })
                        .filter(o -> o != null && keySet.add(o.getFirst()))
                        .collect(HashMap<String, List<String>>::new, (m, d) -> m.put(d.getFirst(), Arrays.asList(d.getSecond().split(","))),
                                HashMap::putAll));
            }
            propMap.put(DEFAULT_LABEL_VALUES, map);
        }
        return map.entrySet().stream().flatMap(e -> {

import java.io.IOException;
import java.net.URI;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;