Scanning in JDK17

[johandevarwaere]

We've currently integrated an Avision IDA6 photo scanner into an Oracle Java 8 32 bit application. We're are going to migrate to Oracle JDK17 64 bit.

We start the scan like this: DTwainAcquisitionArray acquireResult = twainApi.DTWAIN_AcquireNative(twainSourceId, DTwainPixelType.PIXELTYPE_DEFAULT, 1, false, true); In the java 8 32 bit application the scan starts immediately. Launching the same application in java 8 64 bit (with corresponding dlls loaded) works fine as well. But when I launch with Oracle JDK 17 64 bit, nothing happens. 'acquireResult.getNumAcquisitions()' returns 0 But I cant see an error/exception being thrown. Do you have any idea what might cause this behaviour?

Kind regards, Johan

[dynarithmic]

I would highly suggest migrating to the latest Java interface to DTWAIN and attempting the demo programs there.

If the simplest demo doesn't work with Oracle JDK17, then I will take a look further.

[dynarithmic]

I quickly downloaded the Oracle JDK 17, and ran the demo program com.dtwain.demos.SetJNIVersionDemo.java.

1) I am using Eclipse to run the program. 2) I made sure that I am using the jdk-17 JRE. 3) The demo program starts by prompting you which JNI version to use. Choose '4' (64-bit Unicode). 4) If everything is working correctly, you should get a response in the console the DTWAIN DLL that is in use, the path where the DLL is found, and the JNI version in use.

I modified the demo slightly by allowing a selection of a TWAIN Source. After building and running the modified program, I had no issues selecting the TWAIN Working Group sample data source using jdk-17.

Here is the full program:

import java.util.Scanner;
import com.dynarithmic.twain.DTwainGlobalOptions;
import com.dynarithmic.twain.highlevel.TwainSession;
import com.dynarithmic.twain.highlevel.TwainSource;

public class SetJNIVersionDemo
{
    // Simple acquire to a file
    public void run() throws Exception
    {
        System.out.println("Please choose the JNI to use for your application:\n");
        System.out.println("  1. 32-bit ANSI");
        System.out.println("  2. 32-bit Unicode");
        System.out.println("  3. 64-bit ANSI");
        System.out.println("  4. 64-bit Unicode");
        System.out.println("  5. 32-bit ANSI Debug");
        System.out.println("  6. 32-bit Unicode Debug");
        System.out.println("  7. 64-bit ANSI Debug");
        System.out.println("  8. 64-bit Unicode Debug");
        System.out.print("(1 - 8): ");

        @SuppressWarnings("resource")
        Scanner input = new Scanner(System.in);
        int jniToUse = input.nextInt();
        if ( jniToUse < 1 || jniToUse > 8)
            System.out.println("Invalid choice");
        else
        {
            // Set the JNI version
            DTwainGlobalOptions.setJNIVersion(jniToUse - 1);

            // Start a TWAIN session
            TwainSession twainSession = new TwainSession();

            // Verify these are the DLLs being used
            System.out.println("The DTWAIN DLL in use: " + twainSession.getDTwainPath());
            System.out.println("The JNI Version: " + DTwainGlobalOptions.getJNIVersionAsString());

            TwainSource source = twainSession.selectSource();
            if ( source.isOpened())
                System.out.println("The name of the source is " + source.getInfo().getProductName());
            // Close down the TWAIN Session
            twainSession.stop();
        }
    }

    public static void main(String [] args)
    {
        SetJNIVersionDemo s = new SetJNIVersionDemo();
        try
        {
            s.run();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

The console should look something like this when running the program and if you select your scanner in the TWAIN dialog:

Please choose the JNI to use for your application:

  1. 32-bit ANSI
  2. 32-bit Unicode
  3. 64-bit ANSI
  4. 64-bit Unicode
  5. 32-bit ANSI Debug
  6. 32-bit Unicode Debug
  7. 64-bit ANSI Debug
  8. 64-bit Unicode Debug
(1 - 8): 4
The DTWAIN DLL in use: c:\dtwain_bin\DTWAIN64U.dll
The JNI Version: JNI_64U
The name of the source is <name of the scanner>

[johandevarwaere]

Thanks for your quick reply.

I've tried your example, but I run into an error: Exception in thread "main" java.lang.NoSuchMethodError: static com/dynarithmic/twain/highlevel/TwainCallback;.onTwainEvent(IJ)I

I've followed the guidelines (https://github.com/dynarithmic/twain_library-java). The dtwain (5.3.0.7) and dtwainjni dlls are in the root of the project, and all necessary jar files are included as well.

I've got jdk 17.0.6 installed.

[dynarithmic]

The issue is that the dtwainjni.info file required an update, which is available here.

Replace the existing one with the one in the link.

[dynarithmic]

I also updated master with the latest version.

Basically it was an issue with the signature change of OnTwainEvent differing in versions before the initial release. That should be resolved now.

[johandevarwaere]

It solves the error, I'm able to scan now.

Thank you very much.

[dynarithmic]

That's good to hear.

Just to let you know, the demo program SimpleImageNativeAcquireDemo.java has an example of getting the number of acquired images, similar to what you are attempting to do.

I will close the ticket.