> On 14 Dec 2020, at 10:03, Rory O'Donnell <rory.odonn...@oracle.com> wrote:
>
> ...
> On 14/12/2020 09:45, Martin Grigorov wrote:
>> Hi Rory,
>>
>> Apache Wicket build and tests are OK with JDK 16 b28 for both aarch64 and
>> x86_64 (Ubuntu 20.10)!
>>
>> I had to add --add-opens=java.base/java.io=ALL-UNNAMED to
>> maven-surefire-plugin's JVM arguments because it seems this plugin does not
>> use the (automatic) module name of the Maven project and the JDK sees it as
>> unnamed.
>> And because of this Wicket was not able to install its hooks into Java
>> Serialization API.
>>
>> https://github.com/apache/wicket/commit/b269b6dcc6a7642c5b5211cae60c7fa24dd7e7ef__;!!GqivPVa7Brio!OG8UiKWp8imcsbWbsHgnGZT9g23KrXftUL9elEebSECla8O_rUMab08gGqzzNApXj5k$
Opening the `java.io` package will of course work, but requires all
deployments of Wicket to do so. Maybe there is a better alternative.
I see that `org.apache.wicket.serialize.java.JavaSerializer` is using
`setAccessible(true)` to access the private static method
`latestUserDefinedLoader` in `java.io.ObjectInputStream`. There is a
straightforward way of implementing similar functionality with the
standard java.lang.StackWalker API. If you do this, then the
`--add-opens` can probably be dropped.
Here is an example of such:
static {
PrivilegedAction<StackWalker> pa1 =
() ->
StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE);
PrivilegedAction<ClassLoader> pa2 =
() -> ClassLoader.getPlatformClassLoader();
STACKWALKER = AccessController.doPrivileged(pa1);
PLATFORM_LOADER = AccessController.doPrivileged(pa2);
}
/**
* Returns the first non-null and non-platform class loader (not counting
* class loaders of generated reflection implementation classes) up the
* execution stack, or the platform class loader if only code from the
* bootstrap and platform class loader is on the stack.
*/
private static ClassLoader latestUserDefinedLoader() {
return STACKWALKER.walk(s ->
s.map(StackWalker.StackFrame::getDeclaringClass)
.map(Class::getClassLoader)
.filter(Objects::nonNull)
.filter(cl -> !PLATFORM_LOADER.equals(cl))
.findFirst()
.orElse(PLATFORM_LOADER));
}
Remove the PrivilegedAction / doPrivileged stuff if not interested in
running with a security manager enabled.
Let me know if I can do anything further to help.
-Chris.
