Add @Nullable to some equals parameters.

src/java.base/share/classes/java/lang/constant/DynamicCallSiteDesc.java

@@ -30,6 +30,7 @@
 import java.util.Arrays;
 import java.util.Objects;
 import java.util.stream.Stream;
+import org.jspecify.annotations.Nullable;
 
 import static java.lang.constant.ConstantDescs.CD_String;
 import static java.util.Objects.requireNonNull;
@@ -258,7 +259,7 @@ public CallSite resolveCallSiteDesc(MethodHandles.Lookup lookup) throws Throwabl
      *      is equal to this {@code DynamicCallSiteDesc}.
      */
     @Override
-    public final boolean equals(Object o) {
+    public final boolean equals(@Nullable Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
         DynamicCallSiteDesc specifier = (DynamicCallSiteDesc) o;

src/java.base/share/classes/java/text/ChoiceFormat.java

@@ -44,6 +44,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Objects;
+import org.jspecify.annotations.Nullable;
 
 /**
  * {@code ChoiceFormat} is a concrete subclass of {@code NumberFormat} that
@@ -733,7 +734,7 @@ public String toString() {
      * @see Object#equals(Object)
      */
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (this == obj)                      // quick check
             return true;
         if (obj == null || getClass() != obj.getClass())

src/java.base/share/classes/java/text/DateFormatSymbols.java

@@ -49,6 +49,7 @@
 import java.util.ResourceBundle;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import org.jspecify.annotations.Nullable;
 import sun.util.locale.provider.CalendarDataUtility;
 import sun.util.locale.provider.LocaleProviderAdapter;
 import sun.util.locale.provider.LocaleServiceProviderPool;
@@ -687,7 +688,7 @@ public int hashCode() {
      * @see Object#equals(Object)
      */
     @Override
-    public boolean equals(Object obj)
+    public boolean equals(@Nullable Object obj)
     {
         if (this == obj) return true;
         if (obj == null || getClass() != obj.getClass()) return false;

src/java.base/share/classes/java/text/DecimalFormatSymbols.java

@@ -46,6 +46,7 @@
 import java.util.Currency;
 import java.util.Locale;
 import java.util.Objects;
+import org.jspecify.annotations.Nullable;
 import sun.util.locale.provider.CalendarDataUtility;
 import sun.util.locale.provider.LocaleProviderAdapter;
 import sun.util.locale.provider.LocaleServiceProviderPool;
@@ -762,7 +763,7 @@ public Object clone() {
      * @see Object#equals(Object)
      */
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (this == obj) return true;
         if (obj == null || getClass() != obj.getClass()) return false;
         DecimalFormatSymbols other = (DecimalFormatSymbols) obj;

src/java.base/share/classes/java/text/NumberFormat.java

@@ -52,6 +52,7 @@
 import java.util.Objects;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
+import org.jspecify.annotations.Nullable;
 
 import sun.util.locale.provider.LocaleProviderAdapter;
 import sun.util.locale.provider.LocaleServiceProviderPool;
@@ -864,7 +865,7 @@ public int hashCode() {
      * @see Object#equals(Object)
      */
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (this == obj) {
             return true;
         }