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/*
* Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @bug 8262046
* @summary JVMS 5.4.3 If an attempt by the Java Virtual Machine to resolve a symbolic reference fails
* because an error is thrown that is an instance of LinkageError (or a subclass), then subsequent
* attempts to resolve the reference always fail with the same error that was thrown as a result of
* the initial resolution attempt.
* @run main/othervm SaveResolutionErrorTest
*/
public class SaveResolutionErrorTest {
static byte classfile_for_Tester[];
static byte classfile_for_Loadee[];
public static void main(java.lang.String[] args) throws Exception {
ClassLoader appLoader = SaveResolutionErrorTest.class.getClassLoader();
classfile_for_Tester = appLoader.getResourceAsStream("SaveResolutionErrorTest$Tester.class").readAllBytes();
classfile_for_Loadee = appLoader.getResourceAsStream("SaveResolutionErrorTest$Loadee.class").readAllBytes();
long started = System.currentTimeMillis();
for (int i = 0; i < 1000; i++) {
System.out.println("Test: " + i);
MyLoader loader = new MyLoader(appLoader);
loader.doTest();
if (System.currentTimeMillis() - started > 100000) {
break;
}
}
System.out.println("Succeed");
}
public static class Tester extends Thread {
static int errorCount = 0;
synchronized static void incrError() {
++ errorCount;
}
public volatile static boolean go = false;
public static void doit() throws Exception {
System.out.println(Tester.class.getClassLoader());
Thread t1 = new Tester();
Thread t2 = new Tester();
t1.start();
t2.start();
go = true;
t1.join();
t2.join();
System.out.println("errorCount = " + errorCount);
if (errorCount != 0 && errorCount != 2) {
throw new RuntimeException("errorCount should be 0 or 2 but is " + errorCount);
}
}
static int foobar;
static boolean debug = false;
public void run() {
while (!go) { Thread.onSpinWait(); }
try {
// The first thread who tries to resolve the CP entry for the "Loadee" class
// should (most likely) result in a resolution error. This error, if it has
// happened, must also be reported by the second thread.
//
// In some rare conditions, the resolution may succeed. In this case, both
// threads must succeed. The reasons is:
//
// The first thread who tries to resolve the CP entry gets a bad class, but
// when it tries to update the CP entry, the second thread has already succeeded in
// loading the class and has set the entry's tag to JVM_CONSTANT_Class.
foobar += Loadee.value;
} catch (Throwable t) {
Throwable cause = t.getCause();
if (cause != null) {
String s = cause.toString();
if (s.equals(t.toString())) { // wrong cause
t.printStackTrace();
throw new RuntimeException("wrong cause");
}
}
if (debug) {
System.out.println(t);
} else {
synchronized (Tester.class) {
// Enable this block to see the stack trace
System.out.println("------");
t.printStackTrace();
System.out.println("");
}
}
incrError();
}
}
}
public static class Loadee {
static int value = 1234;
}
static class MyLoader extends ClassLoader {
static int count;
static byte[] badclass = {1, 2, 3, 4, 5, 6, 7, 8};
static {
registerAsParallelCapable();
}
ClassLoader parent;
MyLoader(ClassLoader parent) {
this.parent = parent;
}
synchronized boolean hack() {
++ count;
if ((count % 2) == 1) {
return true;
} else {
return false;
}
}
public Class loadClass(String name) throws ClassNotFoundException {
if (name.equals("SaveResolutionErrorTest$Loadee")) {
if (hack()) {
return defineClass(name, badclass, 0, badclass.length);
} else {
return defineClass(name, classfile_for_Loadee, 0, classfile_for_Loadee.length);
}
}
if (name.equals("SaveResolutionErrorTest$Tester")) {
return defineClass(name, classfile_for_Tester, 0, classfile_for_Tester.length);
}
return parent.loadClass(name);
}
void doTest() throws Exception {
Class c = Class.forName("SaveResolutionErrorTest$Tester", /*init=*/true, this);
java.lang.reflect.Method m = c.getMethod("doit");
m.invoke(null);
}
}
}
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