src/java.base/share/classes/java/lang/invoke/MethodHandles.java

rev 14297 : 8155106: MHs.Lookup.findConstructor returns handles for array classes

@@ -1008,10 +1008,13 @@
          * @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
          */
         public MethodHandle findConstructor(Class<?> refc, MethodType type) throws NoSuchMethodException, IllegalAccessException {
+            if (refc.isArray()) {
+                throw new NoSuchMethodException("no constructor for array class: " + refc.getName());
+            }
             String name = "<init>";
             MemberName ctor = resolveOrFail(REF_newInvokeSpecial, refc, name, type);
             return getDirectConstructor(refc, ctor);
         }
 

@@ -2219,10 +2222,30 @@
          */
         static final Lookup PUBLIC_LOOKUP = new Lookup(PUBLIC_LOOKUP_CLASS, Lookup.PUBLIC);
     }
 
     /**
+     * Produces a method handle that can construct arrays of a desired type.
+     * The return type of the method handle will be the array type.
+     * The type of its sole argument will be {@code int}, which specifies the size of the array.
+     * @param arrayClass an array type
+     * @return a method handle which can create arrays of the given type
+     * @throws NullPointerException if the argument is {@code null}
+     * @throws IllegalArgumentException if {@code arrayClass} is not an array type
+     * @since 9
+     */
+    public static
+    MethodHandle arrayConstructor(Class<?> arrayClass) throws IllegalArgumentException {
+        if (!arrayClass.isArray()) {
+            throw newIllegalArgumentException("not an array class: " + arrayClass.getName());
+        }
+        MethodHandle ani = MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_Array_newInstance).
+                bindTo(arrayClass.getComponentType());
+        return ani.asType(ani.type().changeReturnType(arrayClass));
+    }
+
+    /**
      * Produces a method handle giving read access to elements of an array.
      * The type of the method handle will have a return type of the array's
      * element type.  Its first argument will be the array type,
      * and the second will be {@code int}.
      * @param arrayClass an array type