Illegal field name when trying to compile with a javax.swing.Action

[David Alayachew]

Also, here is my version info.


$ java --version
openjdk 21-ea 2023-09-19
OpenJDK Runtime Environment (build 21-ea+31-2444)
OpenJDK 64-Bit Server VM (build 21-ea+31-2444, mixed mode, sharing)


$ javac --version
javac 21-ea



On Sun, Aug 6, 2023 at 7:31 PM David Alayachew <davidalayachew at gmail.com>
wrote:

> Hello Amber Dev Team,
>
> I ran into a problem that I am not sure what the cause is. It only seems
> to occur when I am using unnamed variables.
>
>
> Here are the commands that I am using, as well as their outputs.
>
>
> $ javac -g -Xlint:all,-preview,-serial -Xdiags:verbose --enable-preview
> --source 21 GUI.java
> Note: GUI.java uses preview features of Java SE 21.
> Note: Recompile with -Xlint:preview for details.
>
>
> $ java --enable-preview GUI
> Error: LinkageError occurred while loading main class GUI
>         java.lang.ClassFormatError: Illegal field name "" in class GUI
>
> And here is the file that I am using.
>
>
> import javax.swing.JPanel;
> import javax.swing.JLabel;
> import javax.swing.JButton;
> import java.util.function.BiFunction;
>
> public class GUI
> {
>
>    public static void main(String[] args)
>    {
>
>       new GUI(null, null);
>
>    }
>
>    public GUI(final Object characterType, final Object icon)
>    {
>
>    }
>
>    private Object createConstraintPanel()
>    {
>
>       final JPanel constraintPanel = new JPanel();
>       final JButton              button = new JButton();
>
>       CREATE_INPUT_SANITIZATION:
>       {
>
>          BUTTON_ACTION_LISTENER:
>          {
>
>             button
>                .addActionListener
>                (
>                   _ ->
>                   {
>
>                      final BiFunction<String, Integer, JLabel> createLabel
> =
>                         (text, width) ->
>                         {
>
>                            return null;
>
>                         }
>                         ;
>
>                      final JButton remove = new JButton();
>                      remove
>                         .addActionListener
>                         (
>                            _ ->
>                            {
>
>
>                            }
>                         );
>
>                   }
>                )
>                ;
>
>          }
>
>       }
>
>       return constraintPanel;
>
>    }
>
> }
>
> Technically, this issue also occurs if even 1 of the 2 unnamed variables
> is turned into a real variable. But regardless, the point is, this fails at
> run time.
>
> Please let me know if there is anything I am missing.
>
> Thank you for your time and help!
> David Alayachew
>
>
> On Tue, Jul 18, 2023 at 1:54 AM David Alayachew <davidalayachew at gmail.com>
> wrote:
>
>> Ok, ty for the heads up.
>>
>> On Tue, Jul 18, 2023 at 1:18 AM - <liangchenblue at gmail.com> wrote:
>>
>>> Hi David,
>>> Please do not ask for technical support in the development mailing list.
>>> There's no proof that this issue is with the core libraries instead of the
>>> Java compiler or another component.
>>> I have already downloaded your zip, compiled the 4 files with JDK 22 (my
>>> local dev build for another unrelated patch) javac --enable-preview
>>> -release 22 *.java and java --enable-preview ToDoList, which just shows up
>>> a UI without any crash. Without enable-preview, yoru code does not compile
>>> at all for the usage of _ as an identifier.
>>>
>>> This is most likely a problem with the compiler you are using; you have
>>> a gpj file, which probably means you are using jGrasp. Please report this
>>> issue to the relevant parties (i.e. the 3rd-party IDE or whatever supports
>>> using _ as identifer without --enable-preview) instead.
>>>
>>> Chen Liang
>>>
>>> On Tue, Jul 18, 2023 at 11:43 AM David Alayachew <
>>> davidalayachew at gmail.com> wrote:
>>>
>>>> Wait, nevermind. Don't ignore. I was able to recreate this issue on the
>>>> command line using the abovementioned JDK. Could someone come back and take
>>>> a look at this please?
>>>>
>>>> Sorry for jerking everyone around here. I have multiple JDK's and got
>>>> mixed up on which one I was using.
>>>>
>>>> On Sun, Jul 16, 2023 at 2:26 AM David Alayachew <
>>>> davidalayachew at gmail.com> wrote:
>>>>
>>>>> Hmmmm, this one might actually be IDE specific. Please ignore.
>>>>>
>>>>
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