src/java.base/share/classes/java/lang/String.java

*** 170,179 ****
--- 170,180 ----
       * us to avoid recalculating this.
       */
      private boolean hashIsZero; // Default to false;
  
      /** use serialVersionUID from JDK 1.0.2 for interoperability */
+     @java.io.Serial
      private static final long serialVersionUID = -6849794470754667710L;
  
      /**
       * If String compaction is disabled, the bytes in {@code value} are
       * always encoded in UTF16.
*** 222,231 ****
--- 223,233 ----
       *
       * A String instance is written into an ObjectOutputStream according to
       * <a href="{@docRoot}/../specs/serialization/protocol.html#stream-elements">
       * Object Serialization Specification, Section 6.2, "Stream Elements"</a>
       */
+     @java.io.Serial
      private static final ObjectStreamField[] serialPersistentFields =
          new ObjectStreamField[0];
  
      /**
       * Initializes a newly created {@code String} object so that it represents
*** 1233,1242 ****
--- 1235,1245 ----
      public static final Comparator<String> CASE_INSENSITIVE_ORDER
                                           = new CaseInsensitiveComparator();
      private static class CaseInsensitiveComparator
              implements Comparator<String>, java.io.Serializable {
          // use serialVersionUID from JDK 1.2.2 for interoperability
+         @java.io.Serial
          private static final long serialVersionUID = 8575799808933029326L;
  
          public int compare(String s1, String s2) {
              byte v1[] = s1.value;
              byte v2[] = s2.value;
*** 1248,1257 ****
--- 1251,1261 ----
              return coder == LATIN1 ? StringLatin1.compareToCI_UTF16(v1, v2)
                                     : StringUTF16.compareToCI_Latin1(v1, v2);
          }
  
          /** Replaces the de-serialized object. */
+         @java.io.Serial
          private Object readResolve() { return CASE_INSENSITIVE_ORDER; }
      }
  
      /**
       * Compares two strings lexicographically, ignoring case