JSSC with Windows 10 (64 bit) and Java 9

[wholder]

I'm posting this as a possible "heads up" for a potential future problem for the Arduino IDE. I use JSSC for serial I/O with Java and some time back Arduino switched to JSSC (from RXTX) for its serial I/O, so I think a problem I just started having with JSSC on Windows 10 (64 bit) with the new Java 9 release may potentially be an issue for the Arduino IDE in the future. For details, see the JSSC wiki entry I posted here:

https://github.com/scream3r/java-simple-serial-connector/issues/116

I've included some simple Java test code in the wiki entry that demonstrates the problem but, basically, a call to openPort() to open a serial connection just completely crashes the JVM. I'm not an expert at reading Windows stack traces, but I think the issue my result from this call:

DCB *dcb = new DCB();

in Java_jssc_SerialNativeInterface_openPort().

Wayne

[facchinm]

Hi @wholder ,
thanks for the heads up! We are not planning any switch to Java9 in the upcoming months but of course it could still be a problem if you want to compile the IDE by yourself.

[wholder]

Update: 11-8-2017 Since posting this I have discovered that the issue is more complex than I first thought. The "fixed" code I attached below was built using a 30 day trial version of Visual Studio and was compiled in x64 DEBUG mode and seemed to work. However, when I deinstalled Visual Studio when the 30 day trial period was over, I found that my code would no longer work. Eventually, I discovered a tool called Dependency Walker that let me analyze the DLLs that my revised jSSC-2.8_x86_64.dll relied on and found it needed these other DLLs and, in turn, these DLLs seem to depend on other DLLs that are missing in Windows 10 (and too numerous to list):

• ADVAPI32.DLL
• KERNEL32.DLL
• VCRUNTIME140D.DLL (because I compiled in DEBUG mode)
• UCRTBASED.DLL (because I compiled in DEBUG mode)

I then ran Dependency Walker on the original jSSC-2.8_x86_64.dll file and it reported these DLLs which, as above, each depend on other DLLs that are not available in Windows 10:

• ADVAPI32.DLL
• KERNEL32.DLL
• MSVCRT.DLL
• MSVCRT.DLL

Based on this, I now think a proper fix will require eliminating the need for DLLs that are no longer available in Windows 10.

Wayne

I've managed to create what I think is a reasonably good fix for the problem. It boils down to the way memory was being allocated on the stack in the C++ functions Java_jssc_SerialNativeInterface_openPort() and Java_jssc_SerialNativeInterface_readBytes(). I was able to build a new version of the jSSC-2.8_x86_64.dll file using Visual Studio 2017 and splice it into the jssc.jar library file and it seems to work with Java 9 and Windows 10 (at least in the application in which I'm using JSSC.) However, I'm not really sure how to rebuild all the other native code modules. I'm also not an expert in writing C++ driver code or Windows, so it would helpful if someone else could vet my code. which I've attached below.

Caveat: I found it rather difficult to test my changes to the DLL file as it seem like it would get cached in some cases and I could myself testing what I thought was new code only to find windows using the prior version. To detect this. I would temporarily change the value of the jSSC_NATIVE_LIB_VERSION #define in the jssc_SerialNativeInterface.h file so that I could verify if the new DLL had loaded.

Wayne

jssc.zip

[astout]

I apologize for posting here as it's not entirely related to Arduino, but I have a bootloader that is written in Java that is using jssc and crashes on Windows 10. @wholder, I tried your method of rebuilding with the modified jssc.c++ in Visual Studio (VS). The build was successful, but I am concerned the resulting dll is missing a lot of data because the original jssc-2.8.0.jar windows dll files were 66KB for the x86 version and 120KB for the x86_64 version and after I built them in VS they were 8KB and 9.5KB respectively. I tried inserting them into the .jar anyway but the result was the same, the JVM crashes. Did your dll builds turn out any larger than mine? Would you be willing zip up your resulting dlls and/or the whole jssc-2.8.0.jar and providing those?

EDIT: I found your issue on the java-simple-serial-connector project. I'll redirect my attention there.

[wholder]

I just replied to your post in the JSSC Wiki, but here what I said: I only compiled the 64 bit DLL and, compiling it in debug mode, it came out to be 81.5Kb. If you'd like to try my jssc.jar file, it's posted as part of a project I have posted on Github. The links is: https://github.com/wholder/LaserCut You'll find my modified jssc.jar file in the lib folder. Wayne

…

On Mon, Oct 9, 2017 at 11:15 AM, Alex Stout ***@***.***> wrote: I apologize for posting here as it's not entirely related to Arduino, but I have a bootloader that is written in Java that is using jssc and crashes on Windows 10. @wholder <https://github.com/wholder>, I tried your method of rebuilding with the modified jssc.c++ in Visual Studio (VS). The build was successful, but I am concerned the resulting dll is missing a lot of data because the original jssc-2.8.0.jar windows dll files were 66KB for the x86 version and 120KB for the x86_64 version and after I built them in VS they were 8KB and 9.5KB respectively. I tried inserting them into the .jar anyway but it the result was the same, the JVM crashes. Did your dll builds turn out any larger than mine? Would you be willing zip up your resulting dlls and/or the whole jssc-2.8.0.jar and providing those? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#6788 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABA2ciFjBVgEvWMonuNBkHZexO_cY_Rhks5sqmK-gaJpZM4PrewP> .

[tresf]

FYI, myself and another Java developer forked the JSSC codebase and released a build system as well as updated binaries.

Minus some minor changes for MSVC compat (as well as scripting the version info into the header), you should find the C code to be identical to the official 2.8 release. The Java code has changed a bit to accommodate attempts to use a standardized technique to load the native libs (the portion of the code that locates jssc.dll, etc).

It's running in CI so others can reproduce the build environment locally. Unit tests are incomplete, but the Java and C builds are now documented and live.

Lastly, there are a few platforms that we've dropped support for (ARM soft float and legacy 32-bit/PPC macOS being the most notable) due to a decision to simplify the build system.

Due to some fundamental disagreements with the author of JSSC, our changes are to remain in a fork for the foreseeable future. I wanted to share here for those that could benefit from it.

We've documented all of our tricks to get the .dll working on old Windows versions, etc and I'd be happy to share the techniques used -- notably, optimization and static linking -- by request (email, commit hash or by typing them up).

https://github.com/java-native/jssc/