8257845: Integrate JEP 390

8254047: [JEP 390] Revise "value-based class" & apply to wrappers
8252181: [JEP 390] Define & apply annotation jdk.internal.ValueBased
8252183: [JEP 390] Add 'lint' warning for @ValueBased classes
8257027: [JEP 390] Diagnose synchronization on @ValueBased classes
8252180: [JEP 390] Deprecate wrapper class constructors for removal

Co-authored-by: Roger Riggs <rriggs@openjdk.org>
Co-authored-by: Srikanth Adayapalam <sadayapalam@openjdk.org>
Co-authored-by: Lois Foltan <lfoltan@openjdk.org>
Reviewed-by: rriggs, hseigel, mchung, darcy

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

@@ -122,6 +122,12 @@ import static java.lang.constant.ConstantDescs.DEFAULT_NAME;
  * encoding. For more information on Unicode terminology, refer to the
  * <a href="http://www.unicode.org/glossary/">Unicode Glossary</a>.
  *
+ * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
+ * class; programmers should treat instances that are
+ * {@linkplain #equals(Object) equal} as interchangeable and should not
+ * use instances for synchronization, or unpredictable behavior may
+ * occur. For example, in a future release, synchronization may fail.
+ *
  * @author  Lee Boynton
  * @author  Guy Steele
  * @author  Akira Tanaka
@@ -129,6 +135,7 @@ import static java.lang.constant.ConstantDescs.DEFAULT_NAME;
  * @author  Ulf Zibis
  * @since   1.0
  */
+@jdk.internal.ValueBased
 public final
 class Character implements java.io.Serializable, Comparable<Character>, Constable {
     /**
@@ -8501,7 +8508,7 @@ class Character implements java.io.Serializable, Comparable<Character>, Constabl
      * {@link #valueOf(char)} is generally a better choice, as it is
      * likely to yield significantly better space and time performance.
      */
-    @Deprecated(since="9")
+    @Deprecated(since="9", forRemoval = true)
     public Character(char value) {
         this.value = value;
     }