android/guava/src/com/google/common/collect/Maps.java
public static <K, V> SortedMap<K, V> filterEntries(
      SortedMap<K, V> unfiltered, Predicate<? super Entry<K, V>> entryPredicate) {
    checkNotNull(entryPredicate);
    return (unfiltered instanceof FilteredEntrySortedMap)
        ? filterFiltered((FilteredEntrySortedMap<K, V>) unfiltered, entryPredicate)
        : new FilteredEntrySortedMap<K, V>(checkNotNull(unfiltered), entryPredicate);
  }
public static <K, V> SortedMap<K, V> filterEntries(
      SortedMap<K, V> unfiltered, Predicate<? super Entry<K, V>> entryPredicate) {
    checkNotNull(entryPredicate);
    return (unfiltered instanceof FilteredEntrySortedMap)
        ? filterFiltered((FilteredEntrySortedMap<K, V>) unfiltered, entryPredicate)
        : new FilteredEntrySortedMap<K, V>(checkNotNull(unfiltered), entryPredicate);
  }
Returns a sorted map containing the mappings in {@code unfiltered} that satisfy a predicate.
The returned map is a live view of {@code unfiltered}; changes to one affect the other.

<p>The resulting map's {@code keySet()}, {@code entrySet()}, and {@code values()} views have
iterators that don't support {@code remove()}, but all other methods are supported by the map
and its views. When given a key/value pair that doesn't satisfy the predicate, the map's {@code
put()} and {@code putAll()} methods throw an {@link IllegalArgumentException}. Similarly, the
map's entries have a {@link Entry#setValue} method that throws an {@link
IllegalArgumentException} when the existing key and the provided value don't satisfy the
predicate.

<p>When methods such as {@code removeAll()} and {@code clear()} are called on the filtered map
or its views, only mappings that satisfy the filter will be removed from the underlying map.

<p>The returned map isn't threadsafe or serializable, even if {@code unfiltered} is.

<p>Many of the filtered map's methods, such as {@code size()}, iterate across every key/value
mapping in the underlying map and determine which satisfy the filter. When a live view is
<i>not</i> needed, it may be faster to copy the filtered map and use the copy.

<p><b>Warning:</b> {@code entryPredicate} must be <i>consistent with equals</i>, as documented
at {@link Predicate#apply}.

@since 11.0