src/share/classes/java/util/OptionalDouble.java

rev 8872 : 8028816: Add value-type notice to Optional* classes
Reviewed-by: mduigou
Contributed-by: brian.goetz@oracle.com, bitterfoxc@gmail.com

*** 29,46 ****
  import java.util.function.Supplier;
  
  /**
   * A container object which may or may not contain a {@code double} value.
   * If a value is present, {@code isPresent()} will return {@code true} and
!  * {@code get()} will return the value.
   *
   * <p>Additional methods that depend on the presence or absence of a contained
   * value are provided, such as {@link #orElse(double) orElse()}
   * (return a default value if value not present) and
   * {@link #ifPresent(java.util.function.DoubleConsumer) ifPresent()} (execute a block
   * of code if the value is present).
   *
   * @since 1.8
   */
  public final class OptionalDouble {
      /**
       * Common instance for {@code empty()}.
--- 29,51 ----
  import java.util.function.Supplier;
  
  /**
   * A container object which may or may not contain a {@code double} value.
   * If a value is present, {@code isPresent()} will return {@code true} and
!  * {@code getAsDouble()} will return the value.
   *
   * <p>Additional methods that depend on the presence or absence of a contained
   * value are provided, such as {@link #orElse(double) orElse()}
   * (return a default value if value not present) and
   * {@link #ifPresent(java.util.function.DoubleConsumer) ifPresent()} (execute a block
   * of code if the value is present).
   *
+  * <p>This is a <a href="../lang/doc-files/ValueBased.html">value-based</a>
+  * class; use of identity-sensitive operations (including reference equality
+  * ({@code ==}), identity hash code, or synchronization) on instances of
+  * {@code OptionalDouble} may have unpredictable effects and should be avoided.
+  *
   * @since 1.8
   */
  public final class OptionalDouble {
      /**
       * Common instance for {@code empty()}.