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
1 /*
2 * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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22 */
24 /**
25 * @test
26 * @bug 8003280
27 * @summary Add lambda tests
28 * This test is for identifying SAM types 2 and 3, see Helper.java for SAM types
29 * @compile LambdaTest2_SAM1.java Helper.java
30 * @run main LambdaTest2_SAM1
31 */
33 import java.util.Collections;
34 import java.util.List;
35 import java.util.ArrayList;
36 import java.io.*;
38 public class LambdaTest2_SAM1 {
39 private static List<String> strs = new ArrayList<String>();
40 private static List<File> files = new ArrayList<File>();
42 public static void main(String[] args) {
43 strs.add("copy");
44 strs.add("paste");
45 strs.add("delete");
46 strs.add("rename");
48 files.add(new File("a.txt"));
49 files.add(new File("c.txt"));
50 files.add(new File("b.txt"));
52 //type #2: Comparator<T>
53 Collections.sort(files, (File f1, File f2) -> f1.getName().compareTo(f2.getName()));
54 for(File f : files)
55 System.out.println(f.getName());
56 System.out.println();
57 Collections.sort(files, (File f1, File f2) -> (int)(f1.length() - f2.length()));
58 for(File f : files)
59 System.out.println(f.getName() + " " + f.length());
60 System.out.println();
62 LambdaTest2_SAM1 test = new LambdaTest2_SAM1();
64 //type #2:
65 test.methodMars((File f) -> {
66 System.out.println("implementing Mars<File>.getAge(File f)...");
67 return (int)f.length();
68 });
69 test.methodJupiter((int n) -> n+1);
71 //type #3:
72 test.methodXY((List<String> strList) -> strList.size() );
73 test.methodXYZ((List<String> strList) -> 20 );
74 }
76 //type #2:
77 void methodMars(Mars<File> m) {
78 System.out.println("methodMars(): SAM type interface Mars object instantiated: " + m);
79 System.out.println(m.getAge(new File("a.txt")));
80 }
82 //type #2:
83 void methodJupiter(Jupiter j) {
84 System.out.println("methodJupiter(): SAM type interface Jupiter object instantiated: " + j);
85 System.out.println(j.increment(33));
86 }
88 //type #3:
89 void methodXY(XY xy) {
90 System.out.println("methodXY(): SAM type interface XY object instantiated: " + xy);
91 System.out.println(xy.getTotal(strs));
92 }
94 //type #3:
95 void methodXYZ(XYZ xyz) {
96 System.out.println("methodXYZ(): SAM type interface XYZ object instantiated: " + xyz);
97 System.out.println(xyz.getTotal(strs));
98 }
99 }