diff --git a/api/current.txt b/api/current.txt
index c818205e56f11..e4300f2301591 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -60891,9 +60891,9 @@ package java.lang {
     method @NonNull public StringBuilder reverse();
     method public void setCharAt(int, char);
     method public void setLength(int);
-    method public CharSequence subSequence(int, int);
-    method public String substring(int);
-    method public String substring(int, int);
+    method @NonNull public CharSequence subSequence(int, int);
+    method @NonNull public String substring(int);
+    method @NonNull public String substring(int, int);
     method public void trimToSize();
   }
 
@@ -71226,20 +71226,20 @@ package java.util.concurrent {
     method public boolean addAll(@NonNull java.util.Collection<? extends K>);
     method public final void clear();
     method public boolean contains(@NonNull Object);
-    method public final boolean containsAll(java.util.Collection<?>);
+    method public final boolean containsAll(@NonNull java.util.Collection<?>);
     method public void forEach(@NonNull java.util.function.Consumer<? super K>);
-    method public java.util.concurrent.ConcurrentHashMap<K,V> getMap();
+    method @NonNull public java.util.concurrent.ConcurrentHashMap<K,V> getMap();
     method @Nullable public V getMappedValue();
     method public final boolean isEmpty();
     method @NonNull public java.util.Iterator<K> iterator();
     method public boolean remove(@NonNull Object);
-    method public final boolean removeAll(java.util.Collection<?>);
-    method public final boolean retainAll(java.util.Collection<?>);
+    method public final boolean removeAll(@NonNull java.util.Collection<?>);
+    method public final boolean retainAll(@NonNull java.util.Collection<?>);
     method public final int size();
     method @NonNull public java.util.Spliterator<K> spliterator();
-    method public final Object[] toArray();
-    method public final <T> T[] toArray(T[]);
-    method public final String toString();
+    method @NonNull public final Object[] toArray();
+    method @NonNull public final <T> T[] toArray(@NonNull T[]);
+    method @NonNull public final String toString();
   }
 
   public class ConcurrentLinkedDeque<E> extends java.util.AbstractCollection<E> implements java.util.Deque<E> java.io.Serializable {