1 /*
   2  * Copyright (c) 2016, 2018, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 import sun.hotspot.WhiteBox;
  26 
  27 // package access top-level class to avoid problem with RedefineClassHelper
  28 // and nested types.
  29 class RedefineBasic_B {
  30     public static void okToCallBeforeRedefine() {
  31         System.out.println("okToCallBeforeRedefine");
  32     }
  33     public static void okToCallAfterRedefine() {
  34         throw new RuntimeException("okToCallAfterRedefine is called before redefinition, test failed");
  35     }
  36 }
  37 
  38 public class RedefineBasic {
  39 
  40     public static String newB =
  41         " class RedefineBasic_B { " +
  42         " public static void okToCallBeforeRedefine() { " +
  43         "    throw new RuntimeException(\"newB: okToCallBeforeRedefine is " +
  44         "    called after redefinition, test failed\"); }" +
  45         " public static void okToCallAfterRedefine() { " +
  46         "     System.out.println(\"newB: okToCallAfterRedefine\"); } " +
  47         " } ";
  48 
  49 
  50 
  51     static class SubclassOfB extends RedefineBasic_B {
  52         public static void testAfterRedefine() {
  53             RedefineBasic_B.okToCallAfterRedefine();
  54         }
  55     }
  56 
  57     class Subclass2OfB extends RedefineBasic_B {
  58         public void testAfterRedefine() {
  59             super.okToCallAfterRedefine();
  60         }
  61     }
  62 
  63     // verify that a given class is shared, report error if necessary
  64     public static void
  65     verifyClassIsShared(WhiteBox wb, Class c) throws Exception {
  66         if (!wb.isSharedClass(c)) {
  67             throw new RuntimeException(
  68             "This class should be shared but isn't: " + c.getName());
  69         } else {
  70             System.out.println("The class is shared as expected: " +
  71                 c.getName());
  72         }
  73     }
  74 
  75     public static void main(String[] args) throws Exception {
  76         WhiteBox wb = WhiteBox.getWhiteBox();
  77 
  78         verifyClassIsShared(wb, RedefineBasic.class);
  79         verifyClassIsShared(wb, RedefineBasic_B.class);
  80         verifyClassIsShared(wb, SubclassOfB.class);
  81         verifyClassIsShared(wb, Subclass2OfB.class);
  82 
  83         // (1) Test case: verify that original B works as expected
  84         // and that redefined B is shared and works as expected,
  85         // with new behavior
  86         RedefineBasic_B.okToCallBeforeRedefine();
  87         RedefineClassHelper.redefineClass(RedefineBasic_B.class, newB);
  88         verifyClassIsShared(wb, RedefineBasic_B.class);
  89         RedefineBasic_B.okToCallAfterRedefine();
  90 
  91         // Static subclass of the super:
  92         // 1. Make sure it is still shared
  93         // 2. and it calls the correct super (the redefined one)
  94         verifyClassIsShared(wb, SubclassOfB.class);
  95         SubclassOfB.testAfterRedefine();
  96 
  97         // Same as above, but for non-static class
  98         verifyClassIsShared(wb, Subclass2OfB.class);
  99         RedefineBasic thisTest = new RedefineBasic();
 100         thisTest.testSubclass2OfB();
 101     }
 102 
 103     public void testSubclass2OfB() {
 104         Subclass2OfB sub = new Subclass2OfB();
 105         sub.testAfterRedefine();
 106     }
 107 }