Tue, 14 May 2013 11:11:09 -0700
8012556: Implement lambda methods on interfaces as static
8006140: Javac NPE compiling Lambda expression on initialization expression of static field in interface
Summary: Lambdas occurring in static contexts or those not needing instance information should be generated into static methods. This has long been the case for classes. However, as a work-around to the lack of support for statics on interfaces, interface lambda methods have been generated into default methods. For lambdas in interface static contexts (fields and static methods) this causes an NPE in javac because there is no 'this'. MethodHandles now support static methods on interfaces. This changeset allows lambda methods to be generated as static interface methods. An existing bug in Hotspot (8013875) is exposed in a test when the "-esa" flag is used. This test and another test that already exposed this bug have been marked with @ignore.
Reviewed-by: mcimadamore
aoqi@0 | 1 | /* |
aoqi@0 | 2 | * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved. |
aoqi@0 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
aoqi@0 | 4 | * |
aoqi@0 | 5 | * This code is free software; you can redistribute it and/or modify it |
aoqi@0 | 6 | * under the terms of the GNU General Public License version 2 only, as |
aoqi@0 | 7 | * published by the Free Software Foundation. |
aoqi@0 | 8 | * |
aoqi@0 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
aoqi@0 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
aoqi@0 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
aoqi@0 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
aoqi@0 | 13 | * accompanied this code). |
aoqi@0 | 14 | * |
aoqi@0 | 15 | * You should have received a copy of the GNU General Public License version |
aoqi@0 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
aoqi@0 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
aoqi@0 | 18 | * |
aoqi@0 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
aoqi@0 | 20 | * or visit www.oracle.com if you need additional information or have any |
aoqi@0 | 21 | * questions. |
aoqi@0 | 22 | */ |
aoqi@0 | 23 | |
aoqi@0 | 24 | /** |
aoqi@0 | 25 | * @test |
aoqi@0 | 26 | * @bug 8003280 |
aoqi@0 | 27 | * @summary Add lambda tests |
aoqi@0 | 28 | * This test is for generic methods whose type is the same as the type |
aoqi@0 | 29 | of the generic SAM interface that is taken as the parameter of the |
aoqi@0 | 30 | generic method; the type can be inferred from the value of the other |
aoqi@0 | 31 | type arguments |
aoqi@0 | 32 | * @compile InferenceTest4.java |
aoqi@0 | 33 | * @run main InferenceTest4 |
aoqi@0 | 34 | */ |
aoqi@0 | 35 | |
aoqi@0 | 36 | import java.util.List; |
aoqi@0 | 37 | import java.util.ArrayList; |
aoqi@0 | 38 | |
aoqi@0 | 39 | public class InferenceTest4 { |
aoqi@0 | 40 | |
aoqi@0 | 41 | private static void assertTrue(boolean b) { |
aoqi@0 | 42 | if(!b) |
aoqi@0 | 43 | throw new AssertionError(); |
aoqi@0 | 44 | } |
aoqi@0 | 45 | |
aoqi@0 | 46 | public static void main(String[] args) { |
aoqi@0 | 47 | InferenceTest4 test = new InferenceTest4(); |
aoqi@0 | 48 | test.method1(n -> n.size(), "abc", "java.lang.String"); |
aoqi@0 | 49 | test.method1(n -> n.size(), 'c', "java.lang.Character"); |
aoqi@0 | 50 | test.method1(n -> n.size(), 0, "java.lang.Integer"); |
aoqi@0 | 51 | test.method1(n -> n.size(), 0.1, "java.lang.Double"); |
aoqi@0 | 52 | test.method1(n -> n.size(), 0.1f, "java.lang.Float"); |
aoqi@0 | 53 | test.method1(n -> n.size(), 0L, "java.lang.Long"); |
aoqi@0 | 54 | test.method1(n -> n.size(), (short)0, "java.lang.Short"); |
aoqi@0 | 55 | test.method1(n -> n.size(), (byte)0, "java.lang.Byte"); |
aoqi@0 | 56 | test.method1(n -> n.size(), true, "java.lang.Boolean"); |
aoqi@0 | 57 | test.method1(n -> n.size(), new int[]{1, 2, 3}, "[I"); |
aoqi@0 | 58 | test.method1(n -> n.size(), new double[]{1.0}, "[D"); |
aoqi@0 | 59 | test.method1(n -> n.size(), new String[]{}, "[Ljava.lang.String;"); |
aoqi@0 | 60 | } |
aoqi@0 | 61 | |
aoqi@0 | 62 | <T> void method1(SAM1<T> s, T t, String className) { |
aoqi@0 | 63 | List<T> list = new ArrayList<T>(); |
aoqi@0 | 64 | System.out.println(className + "-" + t.getClass().getName()); |
aoqi@0 | 65 | assertTrue(t.getClass().getName().equals(className)); |
aoqi@0 | 66 | list.add(t); |
aoqi@0 | 67 | assertTrue(s.m1(list) == 1); |
aoqi@0 | 68 | } |
aoqi@0 | 69 | |
aoqi@0 | 70 | interface SAM1<T> { |
aoqi@0 | 71 | int m1(List<T> x); |
aoqi@0 | 72 | } |
aoqi@0 | 73 | } |