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

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

*** 1008,1017 ****
--- 1008,1020 ----
           * @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);
          }
  
*** 2219,2228 ****
--- 2222,2251 ----
           */
          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