diff --git a/src/java.base/share/classes/java/util/stream/Collectors.java b/src/java.base/share/classes/java/util/stream/Collectors.java
index fab29d68541..200af2a8f83 100644
--- a/src/java.base/share/classes/java/util/stream/Collectors.java
+++ b/src/java.base/share/classes/java/util/stream/Collectors.java
@@ -1913,7 +1913,7 @@ public void accept(T t) {
      * @return a {@code Collector} which aggregates the results of two supplied collectors.
      * @since 12
      */
-    public static <T, R1, R2, R>
+    public static <T extends @Nullable Object, R1 extends @Nullable Object, R2 extends @Nullable Object, R extends @Nullable Object>
     Collector<T, ?, R> teeing(Collector<? super T, ?, R1> downstream1,
                               Collector<? super T, ?, R2> downstream2,
                               BiFunction<? super R1, ? super R2, R> merger) {
diff --git a/src/java.base/share/classes/java/util/stream/Stream.java b/src/java.base/share/classes/java/util/stream/Stream.java
index 70e7539ba2a..88ee9f4a869 100644
--- a/src/java.base/share/classes/java/util/stream/Stream.java
+++ b/src/java.base/share/classes/java/util/stream/Stream.java
@@ -429,7 +429,7 @@ public interface Stream<T extends @Nullable Object> extends BaseStream<T, Stream
      * @see #flatMap flatMap
      * @since 16
      */
-    default <R> Stream<R> mapMulti(BiConsumer<? super T, ? super Consumer<R>> mapper) {
+    default <R extends @Nullable Object> Stream<R> mapMulti(BiConsumer<? super T, ? super Consumer<R>> mapper) {
         Objects.requireNonNull(mapper);
         return flatMap(e -> {
             SpinedBuffer<R> buffer = new SpinedBuffer<>();