FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
If first implicit class load failed, the next implicit class loads will continue to fail，even when explicit class load can succeed.

The problem is in JDK6/JDK7/JDK8, but not in JDK5.

THE PROBLEM WAS REPRODUCIBLE WITH -Xint FLAG: Yes

THE PROBLEM WAS REPRODUCIBLE WITH -server FLAG: Yes

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run test case.

EXPECTED VERSUS ACTUAL BEHAVIOR :
+++++++++++++++++++ Expected and in JDK5 +++++++++++++++++++
==============testImplicitClassLoad=====================
implicit class load failed. java.lang.NoClassDefFoundError: test/A
==============testImplicitClassLoad=====================
B
==============testImplicitClassLoad=====================
B
==============testExplicitClassLoad=====================
test.B loaded...class test.B
test.A loaded...class test.A

++++++++++++++++++++++++++++++++++++++++++++++++++

+++++++++++++++++++++ In JDK7 +++++++++++++++++++++++

==============testImplicitClassLoad=====================
implicit class load failed. java.lang.NoClassDefFoundError: test/A
==============testImplicitClassLoad=====================
implicit class load failed. java.lang.NoClassDefFoundError: test/B
==============testImplicitClassLoad=====================
implicit class load failed. java.lang.NoClassDefFoundError: test/B
==============testExplicitClassLoad=====================
test.B loaded...class test.B
test.A loaded...class test.A

++++++++++++++++++++++++++++++++++++++++++++++++++

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package test;

public class A {
public void print() {
System.out.println("A");
}
}
========================================
package test;

public class B extends A{
@Override
public void print() {
System.out.println("B");
}
}
========================================
package test;

public class C {
public void print() {
new B().print();
}
}
=========================================
package test;

import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.concurrent.atomic.AtomicInteger;

public class Test {

public static void main(String[] args) throws Exception {

MyClassLoader myClassLoader = new MyClassLoader();

Class cClass = myClassLoader.loadClass("test.C");
Object cObject = cClass.newInstance();
Method printMethod = cClass.getMethod("print");

testImplicitClassLoad(cObject, printMethod);

testExplicitClassLoad(myClassLoader);
}

private static void testImplicitClassLoad(Object cObject, Method printMethod) {
for (int i = 0; i < 3; i++) {
System.out.println("==============testImplicitClassLoad=====================");
try {
printMethod.invoke(cObject);
} catch (Exception e) {
System.out.println("implicit class load failed. " + e.getCause());
}
}
}

private static void testExplicitClassLoad(ClassLoader classLoader) throws ClassNotFoundException {
System.out.println("==============testExplicitClassLoad=====================");
System.out.println("test.B loaded..." + classLoader.loadClass("test.B"));
System.out.println("test.A loaded..." + classLoader.loadClass("test.A"));
}
}

class MyClassLoader extends URLClassLoader {

private AtomicInteger count = new AtomicInteger(0);

public MyClassLoader() {
super(getMyURLs(), null);
}

private static URL[] getMyURLs() {
URL[] urls = {Thread.currentThread().getContextClassLoader().getResource("")};
return urls;
}

@Override
protected Class<?> loadClass(String name, boolean resolve)
throws ClassNotFoundException {
//System.out.println(name);

if (name.contains("A") && count.getAndIncrement() == 0)
{
throw new ClassNotFoundException("A");
}

return super.loadClass(name, resolve);
}
}


---------- END SOURCE ----------