Add a few missing @Nullable annotations.

src/java.base/share/classes/java/security/MessageDigest.java

@@ -322,7 +322,7 @@ public static MessageDigest getInstance(String algorithm,
      *
      * @return the provider of this message digest object
      */
-    public final Provider getProvider() {
+    public final @Nullable Provider getProvider() {
         return this.provider;
     }
 
@@ -480,7 +480,7 @@ public String toString() {
      *
      * @return {@code true} if the digests are equal, {@code false} otherwise.
      */
-    public static boolean isEqual(byte[] digesta, byte[] digestb) {
+    public static boolean isEqual(byte @Nullable [] digesta, byte @Nullable [] digestb) {
         if (digesta == digestb) return true;
         if (digesta == null || digestb == null) {
             return false;

src/java.base/share/classes/java/util/ResourceBundle.java

@@ -456,7 +456,7 @@ public ResourceBundle newResourceBundle(Class<? extends ResourceBundle> bundleCl
      *
      * @since 1.8
      */
-    public String getBaseBundleName() {
+    public @Nullable String getBaseBundleName() {
         return name;
     }
 
@@ -612,7 +612,7 @@ private static ClassLoader getLoaderForControl(Module module) {
      *
      * @param parent this bundle's parent bundle.
      */
-    protected void setParent(ResourceBundle parent) {
+    protected void setParent(@Nullable ResourceBundle parent) {
         assert parent != NONEXISTENT_BUNDLE;
         this.parent = parent;
     }
@@ -2247,7 +2247,7 @@ public static final void clearCache(ClassLoader loader) {
      * @throws    NullPointerException if {@code key} is {@code null}
      * @return the object for the given key, or null
      */
-    protected abstract Object handleGetObject(String key);
+    protected abstract @Nullable Object handleGetObject(String key);
 
     /**
      * Returns an enumeration of the keys.
@@ -2988,7 +2988,7 @@ private static List<Locale> getDefaultList(String language, String script, Strin
          *        if {@code baseName} or {@code locale}
          *        is {@code null}
          */
-        public Locale getFallbackLocale(String baseName, Locale locale) {
+        public @Nullable Locale getFallbackLocale(String baseName, Locale locale) {
             if (baseName == null) {
                 throw new NullPointerException();
             }
@@ -3106,7 +3106,7 @@ public Locale getFallbackLocale(String baseName, Locale locale) {
          *        any I/O operations
          * @see java.util.spi.ResourceBundleProvider#getBundle(String, Locale)
          */
-        public ResourceBundle newBundle( String baseName, Locale locale, String format,
+        public @Nullable ResourceBundle newBundle( String baseName, Locale locale, String format,
                                         ClassLoader loader, boolean reload)
                     throws IllegalAccessException, InstantiationException, IOException {
             /*

src/java.base/share/classes/java/util/Vector.java

@@ -644,7 +644,7 @@ public synchronized void addElement(E obj) {
      * @return  {@code true} if the argument was a component of this
      *          vector; {@code false} otherwise.
      */
-    public synchronized boolean removeElement(Object obj) {
+    public synchronized boolean removeElement(@Nullable Object obj) {
         modCount++;
         int i = indexOf(obj);
         if (i >= 0) {