On 18/03/2022 10:51 am, Cheng Jin wrote:
Hi Raffaello,
My concern is why the verification happens even without initialization in the
test without mh.invoke() in the main(), which I don't think is covered or
explained in the JVM Spec.
Put it in another way, my understanding is, when the class
OK, from what I read so far from you is that you were surprised about
the order, not about why verification happens even without initialization.
Verification is part of linking, which surely must happen before user
code (e.g., initialization) is executed, which explains the order.
But once
Hi Raffaello,
My concern is why the verification happens even without initialization in the
test without mh.invoke() in the main(), which I don't think is covered or
explained in the JVM Spec.
Put it in another way, my understanding is, when the class gets loaded, it is
verified which doesn't
Cheng,
initialization is the last thing that happens because it's where user
provided code gets executed.
This has always been this way, as long as I can remember. See the JVMS
for the gory details.
Greetings
Raffaello
On 2022-03-18 01:21, Cheng Jin wrote:
Hi David,
1) for the test
Sure, which again shows that Test_2 is not initialized by the lookup of
the mh but only upon its invocation.
Raffaello
On 2022-03-18 00:46, David Holmes wrote:
Run with -Xlog:class+init=info to see the classes that get initialized
and in what order.
David
On 18/03/2022 5:53 am, Raffaello
Hi David,
1) for the test with mh.invoke() in main(), the log shows:
[0.262s][info][class,init] Start class verification for: Test_1
[0.262s][info][class,init] End class verification for: Test_1
[0.263s][info][class,init] 282 Initializing 'Test_1' (0x000800c00800)
[0.263s][info][class,init]
Hi Cheng,
I'm not sure I understand your point. By class initialization I mean
what's specified in the JVMS [1].
Are you concerned with initialization or with verification (which
precedes initialization)?
Raffaello
[1]
Run with -Xlog:class+init=info to see the classes that get initialized
and in what order.
David
On 18/03/2022 5:53 am, Raffaello Giulietti wrote:
Hi again,
here's code that shows that initialization doesn't happen during lookup
but only upon invoking the method handle. (I'm on Java 17.)
Hi Raffaello,
The code snippet I posted previously was not the original test I verified on
Java 17 (which was generated via asmtools to trigger verification)
Here's the pretty much the test I used:
Test_1.java
import java.lang.invoke.*;
public class Test_1 {
static MethodHandle mh;
Hi again,
here's code that shows that initialization doesn't happen during lookup
but only upon invoking the method handle. (I'm on Java 17.)
As long as the 2nd line in main() is commented, you don't see the
message "Test_2 initialized", which shows that the lookup doesn't
initialize
Hi,
as far as I can see, the code should not even compile, as there's a
static field in Test_1 which is initialized with an expression that
throws checked exceptions (findStatic(..)).
In addition, it seems to me that there's nothing in your code that
reveals whether Test_2 has been
- Original Message -
> From: "Cheng Jin"
> To: "core-libs-dev"
> Sent: Thursday, March 17, 2022 5:42:57 PM
> Subject: When to initialize the method's class for
> MethodHandles.Lookup.findStatic()?
> Hi there,
>
> The document of
>
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