1 /*
2  * Copyright (c) 2014, 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 import java.io.DataInputStream;
25 import java.io.File;
26 import java.io.FileInputStream;
27 import java.lang.instrument.ClassDefinition;
28 import java.lang.instrument.Instrumentation;
29 
30 /*
31  * This class is present during compilation, but will be deleted before execution.
32  */
33 class MyUnresolvedClass {
bar()34     static void bar() {
35     }
36 }
37 
38 class MyRedefinedClass {
foo()39     static void foo() {
40         MyUnresolvedClass.bar();
41     }
42 }
43 
44 public class UnresolvedClassAgent {
main(String... args)45     public static void main(String... args) {
46     }
47 
premain(String args, Instrumentation inst)48     public static void premain(String args, Instrumentation inst) throws Exception {
49         try {
50             MyRedefinedClass.foo();
51         } catch(NoClassDefFoundError err) {
52             System.out.println("NoClassDefFoundError (expected)");
53         }
54 
55         File f = new File(System.getProperty("test.classes"), "MyRedefinedClass.class");
56         byte[] buf = new byte[(int)f.length()];
57         try (DataInputStream dis = new DataInputStream(new FileInputStream(f))) {
58             dis.readFully(buf);
59         }
60         ClassDefinition cd = new ClassDefinition(MyRedefinedClass.class, buf);
61         inst.redefineClasses(new ClassDefinition[] {cd});
62 
63         try {
64             MyRedefinedClass.foo();
65         } catch(NoClassDefFoundError err) {
66             System.out.println("NoClassDefFoundError (expected again)");
67         }
68     }
69 }
70