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

*** 31,10 ***
--- 31,11 ---
  import java.util.Optional;
  
  import jdk.internal.math.FloatConsts;
  import jdk.internal.math.FloatingDecimal;
  import jdk.internal.math.FloatToDecimal;
+ import jdk.internal.value.DeserializeConstructor;
  import jdk.internal.vm.annotation.IntrinsicCandidate;
  
  /**
   * The {@code Float} class is the {@linkplain
   * java.lang##wrapperClass wrapper class} for values of the primitive

*** 46,14 ***
   * {@code String} to a {@code float}, as well as other
   * constants and methods useful when dealing with a
   * {@code float}.
   *
   * <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.
   *
   * <h2><a id=equivalenceRelation>Floating-point Equality, Equivalence,
   * and Comparison</a></h2>
   *
   * The class {@code java.lang.Double} has a {@linkplain
--- 47,22 ---
   * {@code String} to a {@code float}, as well as other
   * constants and methods useful when dealing with a
   * {@code float}.
   *
   * <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, mutexes, or
!  * with {@linkplain java.lang.ref.Reference object references}.
!  *
+  * <div class="preview-block">
+  *      <div class="preview-comment">
+  *          When preview features are enabled, {@code Float} is a {@linkplain Class#isValue value class}.
+  *          Use of value class instances for synchronization, mutexes, or with
+  *          {@linkplain java.lang.ref.Reference object references} result in
+  *          {@link IdentityException}.
+  *      </div>
+  * </div>
   *
   * <h2><a id=equivalenceRelation>Floating-point Equality, Equivalence,
   * and Comparison</a></h2>
   *
   * The class {@code java.lang.Double} has a {@linkplain

*** 73,10 ***
--- 82,11 ---
   * @author  Lee Boynton
   * @author  Arthur van Hoff
   * @author  Joseph D. Darcy
   * @since 1.0
   */
+ @jdk.internal.MigratedValueClass
  @jdk.internal.ValueBased
  public final class Float extends Number
          implements Comparable<Float>, Constable, ConstantDesc {
      /**
       * A constant holding the positive infinity of type

*** 572,10 ***
--- 582,11 ---
       * @param  f a float value.
       * @return a {@code Float} instance representing {@code f}.
       * @since  1.5
       */
      @IntrinsicCandidate
+     @DeserializeConstructor
      public static Float valueOf(float f) {
          return new Float(f);
      }
  
      /**