Summary

Correct the wrong specification of MethodHandles.constant(Class,Object) regarding the equivalence with identity(...).bindTo(...).

Problem

The specification stated that the returned MethodHandle is equivalent to creating an identity handle and binding the value to the first parameter. However, this is incorrect for primitive types, which are not supported by MethodHandle::bindTo but are by MethodHandles::constant.

Solution

Replace the wrong example with a combination of identity with MethodHandles::insertArguments, which is actually equivalent.

Specification

    diff --git a/src/java.base/share/classes/java/lang/invoke/MethodHandles.java b/src/java.base/share/classes/java/lang/invoke/MethodHandles.java
--- a/src/java.base/share/classes/java/lang/invoke/MethodHandles.java	(revision 659b53fe33eaa531bca1951a26f357b51902311e)
+++ b/src/java.base/share/classes/java/lang/invoke/MethodHandles.java	(revision 7889ae2e343500e3bcd3da3e90cc9ae3dc7bbff9)
@@ -4826,7 +4826,9 @@
      * Before the method handle is returned, the passed-in value is converted to the requested type.
      * If the requested type is primitive, widening primitive conversions are attempted,
      * else reference conversions are attempted.
-     * <p>The returned method handle is equivalent to {@code identity(type).bindTo(value)}.
+     * <p>The returned method handle is equivalent to {@code identity(type).bindTo(value)},
+     * for reference types.  For all types it is equivalent to
+     * {@code insertArguments(identity(type), 0, value)}.
      * @param type the return type of the desired method handle
      * @param value the value to return
      * @return a method handle of the given return type and no arguments, which always returns the given value