--- a/src/java.base/share/classes/java/lang/invoke/MethodHandles.java Tue Mar 26 14:43:23 2019 -0700
+++ b/src/java.base/share/classes/java/lang/invoke/MethodHandles.java Tue Mar 26 15:53:36 2019 -0700
@@ -422,6 +422,10 @@
* because the desired class member is missing, or because the
* desired class member is not accessible to the lookup class, or
* because the lookup object is not trusted enough to access the member.
+ * In the case of a field setter function on a {@code final} field,
+ * finality enforcement is treated as a kind of access control,
+ * and the lookup will fail, except in special cases of
+ * {@link Lookup#unreflectSetter Lookup.unreflectSetter}.
* In any of these cases, a {@code ReflectiveOperationException} will be
* thrown from the attempted lookup. The exact class will be one of
* the following:
@@ -1438,6 +1442,7 @@
* @return a method handle which can store values into the field
* @throws NoSuchFieldException if the field does not exist
* @throws IllegalAccessException if access checking fails, or if the field is {@code static}
+ * or {@code final}
* @exception SecurityException if a security manager is present and it
* <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
* @throws NullPointerException if any argument is null
@@ -1561,6 +1566,7 @@
* @return a method handle which can store values into the field
* @throws NoSuchFieldException if the field does not exist
* @throws IllegalAccessException if access checking fails, or if the field is not {@code static}
+ * or is {@code final}
* @exception SecurityException if a security manager is present and it
* <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
* @throws NullPointerException if any argument is null
@@ -1840,10 +1846,10 @@
* Produces a method handle giving read access to a reflected field.
* The type of the method handle will have a return type of the field's
* value type.
- * If the field is static, the method handle will take no arguments.
+ * If the field is {@code static}, the method handle will take no arguments.
* Otherwise, its single argument will be the instance containing
* the field.
- * If the field's {@code accessible} flag is not set,
+ * If the {@code Field} object's {@code accessible} flag is not set,
* access checking is performed immediately on behalf of the lookup class.
* <p>
* If the field is static, and
@@ -1857,8 +1863,43 @@
public MethodHandle unreflectGetter(Field f) throws IllegalAccessException {
return unreflectField(f, false);
}
+
+ /**
+ * Produces a method handle giving write access to a reflected field.
+ * The type of the method handle will have a void return type.
+ * If the field is {@code static}, the method handle will take a single
+ * argument, of the field's value type, the value to be stored.
+ * Otherwise, the two arguments will be the instance containing
+ * the field, and the value to be stored.
+ * If the {@code Field} object's {@code accessible} flag is not set,
+ * access checking is performed immediately on behalf of the lookup class.
+ * <p>
+ * If the field is {@code final}, write access will not be
+ * allowed and access checking will fail, except under certain
+ * narrow circumstances documented for {@link Field#set Field.set}.
+ * A method handle is returned only if a corresponding call to
+ * the {@code Field} object's {@code set} method could return
+ * normally. In particular, fields which are both {@code static}
+ * and {@code final} may never be set.
+ * <p>
+ * If the field is {@code static}, and
+ * if the returned method handle is invoked, the field's class will
+ * be initialized, if it has not already been initialized.
+ * @param f the reflected field
+ * @return a method handle which can store values into the reflected field
+ * @throws IllegalAccessException if access checking fails,
+ * or if the field is {@code final} and write access
+ * is not enabled on the {@code Field} object
+ * @throws NullPointerException if the argument is null
+ */
+ public MethodHandle unreflectSetter(Field f) throws IllegalAccessException {
+ return unreflectField(f, true);
+ }
+
private MethodHandle unreflectField(Field f, boolean isSetter) throws IllegalAccessException {
MemberName field = new MemberName(f, isSetter);
+ if (isSetter && field.isStatic() && field.isFinal())
+ throw field.makeAccessException("static final field has no write access", this);
assert(isSetter
? MethodHandleNatives.refKindIsSetter(field.getReferenceKind())
: MethodHandleNatives.refKindIsGetter(field.getReferenceKind()));
@@ -1868,28 +1909,6 @@
}
/**
- * Produces a method handle giving write access to a reflected field.
- * The type of the method handle will have a void return type.
- * If the field is static, the method handle will take a single
- * argument, of the field's value type, the value to be stored.
- * Otherwise, the two arguments will be the instance containing
- * the field, and the value to be stored.
- * If the field's {@code accessible} flag is not set,
- * access checking is performed immediately on behalf of the lookup class.
- * <p>
- * If the field is static, and
- * if the returned method handle is invoked, the field's class will
- * be initialized, if it has not already been initialized.
- * @param f the reflected field
- * @return a method handle which can store values into the reflected field
- * @throws IllegalAccessException if access checking fails
- * @throws NullPointerException if the argument is null
- */
- public MethodHandle unreflectSetter(Field f) throws IllegalAccessException {
- return unreflectField(f, true);
- }
-
- /**
* Produces a VarHandle giving access to a reflected field {@code f}
* of type {@code T} declared in a class of type {@code R}.
* The VarHandle's variable type is {@code T}.