CODEWITHSUNDEEP
graalvmusb4java
Simon K
Simon K

Reputation: 59

usb4java GraalVM native compatibility issues

We have a SpringBoot3 app that communicates with virtual UART port via USB. App runs just fine as a JAR, however, there are strange issues we face once it gets compiled to a native .exe using GraalVM. Some methods of usb4java work fine, some work only partially and one method even causes a segfault.

For example,

Context context = new Context();
int result = LibUsb.init(context);

will result in

java.lang.UnsupportedOperationException: null not supported as key!

while calling it as

LibUsb.init(null);

will work just fine,

list = new DeviceList();
result = LibUsb.getDeviceList(context, list);

works alright, as well as

Version version = LibUsb.getVersion();

however, calling

descriptor = new DeviceDescriptor();
result = LibUsb.getDeviceDescriptor(device, descriptor);

causes segfault right away. Once again, none of this happens given app is run as jar.

Was able to find very little info on that issue on the Internets.

Upvotes: 0

Views: 58

Answers (1)

Simon K
Simon K

Reputation: 59

Looks like have it sorted. All these glitches happen because of missing method fields in jni-config.json, once

{
  "name":"org.usb4java.Context",
  "fields":[{"name":"contextPointer"}]
},
{
  "name":"org.usb4java.Device",
  "fields":[{"name":"devicePointer"}],
  "methods":[{"name":"<init>","parameterTypes":[] }]
},
{
  "name":"org.usb4java.DeviceDescriptor",
  "fields":[{"name":"deviceDescriptorBuffer"}, {"name":"deviceDescriptorPointer"}]
},
{
  "name":"org.usb4java.DeviceList",
  "fields":[{"name":"deviceListPointer"}, {"name":"size"}]
},

added, the problem's gone.

Upvotes: 0

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