1 /*
   2 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
   3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4 *
   5 * This code is free software; you can redistribute it and/or modify it
   6 * under the terms of the GNU General Public License version 2 only, as
   7 * published by the Free Software Foundation.  Oracle designates this
   8 * particular file as subject to the "Classpath" exception as provided
   9 * by Oracle in the LICENSE file that accompanied this code.
  10 *
  11 * This code is distributed in the hope that it will be useful, but WITHOUT
  12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 * version 2 for more details (a copy is included in the LICENSE file that
  15 * accompanied this code).
  16 *
  17 * You should have received a copy of the GNU General Public License version
  18 * 2 along with this work; if not, write to the Free Software Foundation,
  19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20 *
  21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22 * or visit www.oracle.com if you need additional information or have any
  23 * questions.
  24 */
  25 
  26 /*
  27  * Create class file using ASM, slightly modified the ASMifier output
  28 */
  29 
  30 
  31 
  32 import java.io.File;
  33 import java.io.FileOutputStream;
  34 import java.io.IOException;
  35 import jdk.internal.org.objectweb.asm.*;
  36 
  37 
  38 public class ClassFileGenerator {
  39 
  40     public static void main(String... args) throws Exception {
  41         classFileWriter("AnnoationWithVoidReturn.class", AnnoationWithVoidReturnDump.dump());
  42         classFileWriter("AnnoationWithParameter.class", AnnoationWithParameterDump.dump());
  43     }
  44 
  45     private static void classFileWriter(String name, byte[] contents) throws IOException {
  46         try (FileOutputStream fos = new FileOutputStream(new File(System.getProperty("test.classes"),
  47                 name))) {
  48             fos.write(contents);
  49         }
  50     }
  51 
  52     /*
  53     Following code create equivalent classfile, 
  54     which is not allowed by javac.
  55     @Retention(RetentionPolicy.RUNTIME)
  56     public @interface AnnoationWithVoidReturn {
  57     void m() default 1;
  58     }
  59     */
  60 
  61     private static class AnnoationWithVoidReturnDump implements Opcodes {
  62         public static byte[] dump() throws Exception {
  63             ClassWriter cw = new ClassWriter(0);
  64             MethodVisitor mv;
  65             AnnotationVisitor av0;
  66 
  67             cw.visit(52, ACC_PUBLIC + ACC_ANNOTATION + ACC_ABSTRACT + +ACC_INTERFACE,
  68                     "AnnoationWithVoidReturn", null,
  69                     "java/lang/Object", new String[]{"java/lang/annotation/Annotation"});
  70 
  71             {
  72                 av0 = cw.visitAnnotation("Ljava/lang/annotation/Retention;", true);
  73                 av0.visitEnum("value", "Ljava/lang/annotation/RetentionPolicy;",
  74                         "RUNTIME");
  75                 av0.visitEnd();
  76             }
  77             {
  78                 mv = cw.visitMethod(ACC_PUBLIC + ACC_ABSTRACT, "m", "()V", null, null);
  79                 mv.visitEnd();
  80             }
  81             {
  82                 av0 = mv.visitAnnotationDefault();
  83                 av0.visit(null, new Integer(1));
  84                 av0.visitEnd();
  85             }
  86             cw.visitEnd();
  87 
  88             return cw.toByteArray();
  89 
  90         }
  91     }
  92 
  93     /*
  94     Following code create equivalent classfile, 
  95     which is not allowed by javac.
  96     @Retention(RetentionPolicy.RUNTIME)
  97     public @interface AnnoationWithParameter {
  98        int m(int x);
  99     }
 100     */
 101 
 102     private static class AnnoationWithParameterDump implements Opcodes {
 103         public static byte[] dump() throws Exception {
 104 
 105             ClassWriter cw = new ClassWriter(0);
 106             MethodVisitor mv;
 107             AnnotationVisitor av0;
 108 
 109             cw.visit(52, ACC_PUBLIC + ACC_ANNOTATION + ACC_ABSTRACT + ACC_INTERFACE,
 110                     "AnnoationWithParameter", null,
 111                     "java/lang/Object", new String[]{"java/lang/annotation/Annotation"});
 112 
 113             {
 114                 av0 = cw.visitAnnotation("Ljava/lang/annotation/Retention;", true);
 115                 av0.visitEnum("value", "Ljava/lang/annotation/RetentionPolicy;",
 116                         "RUNTIME");
 117                 av0.visitEnd();
 118             }
 119             {
 120                 mv = cw.visitMethod(ACC_PUBLIC + ACC_ABSTRACT,
 121                         "badValue",
 122                         "(I)I", // Bad method with a parameter
 123                         null, null);
 124                 mv.visitEnd();
 125             }
 126             {
 127                 av0 = mv.visitAnnotationDefault();
 128                 av0.visit(null, new Integer(-1));
 129                 av0.visitEnd();
 130             }
 131             cw.visitEnd();
 132 
 133             return cw.toByteArray();
 134         }
 135     }
 136 
 137 }