package p; import org.jetbrains.annotations.NotNull; import org.jetbrains.annotations.Nullable; import java.util.Collection; import java.util.Collections; import java.util.Map; import java.util.Set; class M implements Map { public int size() { return 0; } public boolean isEmpty() { return false; } public boolean containsKey(Object o) { return false; } public boolean containsValue(Object o) { return false; } public Object get(Object o) { return null; } @Nullable public Object put(Object o, Object o2) { return null; } public Object remove(Object o) { return null; } public void putAll(@NotNull Map map) { } public void clear() { } @NotNull public Set keySet() { return Collections.emptySet(); } @NotNull public Collection values() { return Collections.emptyList(); } @NotNull public Set entrySet() { return Collections.emptySet(); } }