@Override
  public SortedMap<K, V> subMap(@ParametricNullness K fromKey, @ParametricNullness K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  @Override
  public SortedMap<K, V> headMap(@ParametricNullness K toKey) {
    return headMap(toKey, false);
  }

  @Override
  public SortedMap<K, V> tailMap(@ParametricNullness K fromKey) {

        delegate.subMap(checkValid(fromKey), fromInclusive, checkValid(toKey), toInclusive));
  }

  @Override
  public SortedMap<K, V> subMap(K fromKey, K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  @Override
  public SortedMap<K, V> tailMap(K fromKey) {
    return tailMap(fromKey, true);
  }

  @Override
  public NavigableMap<K, V> tailMap(K fromKey, boolean inclusive) {

import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.SortedMap;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests operations on a SortedMap. Can't be invoked directly; please see
 * {@code SortedMapTestSuiteBuilder}.
 *
 * @author Jesse Wilson
 * @author Louis Wasserman
 */
@GwtCompatible

 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import java.util.SortedMap;

@GwtCompatible
public class ImmutableSortedMapSubMapMapInterfaceTest
    extends AbstractImmutableSortedMapMapInterfaceTest<String, Integer> {
  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    return ImmutableSortedMap.of("a", 1, "b", 2, "c", 3, "d", 4, "e", 5).subMap("b", "d");
  }

 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import java.util.SortedMap;

@GwtCompatible
public class ImmutableSortedMapTailMapMapInterfaceTest
    extends AbstractImmutableSortedMapMapInterfaceTest<String, Integer> {
  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    return ImmutableSortedMap.of("a", 1, "b", 2, "c", 3, "d", 4, "e", 5).tailMap("b");
  }

 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import java.util.SortedMap;

@GwtCompatible
public class ImmutableSortedMapTailMapMapInterfaceTest
    extends AbstractImmutableSortedMapMapInterfaceTest<String, Integer> {
  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    return ImmutableSortedMap.of("a", 1, "b", 2, "c", 3, "d", 4, "e", 5).tailMap("b");
  }

import com.google.common.testing.SerializableTester;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NavigableMap;
import java.util.SortedMap;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

/**
 * Tests for SafeTreeMap.
 *
 * @author Louis Wasserman
 */

import com.google.common.testing.SerializableTester;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NavigableMap;
import java.util.SortedMap;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

/**
 * Tests for SafeTreeMap.
 *
 * @author Louis Wasserman
 */

    public K firstKey() {
      return standardFirstKey();
    }

    @Override
    public SortedMap<K, V> headMap(K toKey) {
      return standardHeadMap(toKey);
    }

    @Override
    public K lastKey() {
      return standardLastKey();
    }

    @Override
    public SortedMap<K, V> tailMap(K fromKey) {
      return standardTailMap(fromKey);
    }
  }

 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import java.util.SortedMap;

@GwtCompatible
public class ImmutableSortedMapHeadMapInclusiveMapInterfaceTest
    extends AbstractImmutableSortedMapMapInterfaceTest<String, Integer> {
  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    return ImmutableSortedMap.of("a", 1, "b", 2, "c", 3, "d", 4, "e", 5).headMap("c", true);