Invalid memory access with multithreading

[omasseau]

I'm using the high level API with the latest version of ghost4j (built from Latest commit 52cd8f2 on 5 May 2016) to convert pdfs to postscript The documentation says the high level API is thread safe.

But this does not seems the case. Here is my code:

    /**
     * Convert a pdf file to postscript. 
     * Note: Ghostscript must be installed on the system.
     * @param pdfInputStream The pdf input stream.
     * @param psOutputStream The postcript output stream.
     * @throws Exception
     */
    public static void convertPdfToPostscript(InputStream pdfInputStream, OutputStream psOutputStream) throws Exception {

        try {

            PDFDocument document = new PDFDocument();
            document.load(pdfInputStream); 

            PSConverter converter = new PSConverter();
            converter.setMaxProcessCount(0);
            converter.setDevice(PSConverter.OPTION_DEVICE_PS2WRITE);
            converter.convert(document, psOutputStream); 

        } catch (Exception e) {
            throw new Exception("Could not convert pdf to postscript", e);
        }
    }

But I still get an 'Invalid memory access' error when calling it from 2 threads at the same time:

java.lang.Error: Invalid memory access at com.sun.jna.Native.invokeInt(Native Method) at com.sun.jna.Function.invoke(Function.java:383) at com.sun.jna.Function.invoke(Function.java:315) at com.sun.jna.Library$Handler.invoke(Library.java:212) at com.sun.proxy.$Proxy202.gsapi_init_with_args(Unknown Source) at org.ghost4j.Ghostscript.initialize(Ghostscript.java:350) at org.ghost4j.converter.PSConverter.run(PSConverter.java:142) at org.ghost4j.converter.AbstractRemoteConverter.convert(AbstractRemoteConverter.java:85) at com.real.aof.helper.PdfHelper.convertPdfToPostscript(PdfHelper.java:2573)

[omasseau]

Test code to reproduce the problem:

public static void main(String[] args) throws Exception {

        String input = "C:/Users/maol/Developments/AOF/Tests/pdf/pdf-images/16-pages-of-text-image.pdf";

        final ByteArrayInputStream bais1 = new ByteArrayInputStream(Files.readAllBytes(Paths.get(input)));
        final ByteArrayInputStream bais2 = new ByteArrayInputStream(Files.readAllBytes(Paths.get(input)));

        final ByteArrayOutputStream baos1 = new ByteArrayOutputStream();

        final ByteArrayOutputStream baos2 = new ByteArrayOutputStream();

        Thread t1 = new Thread() {
            public void run() {
                try {
                    convertPdfToPostscript(bais1, baos1);
                } catch (Exception e) {
                    e.printStackTrace();
                }   
            }
        };

        Thread t2 = new Thread() {
            public void run() {
                try {
                    convertPdfToPostscript(bais2, baos2);
                } catch (Exception e) {
                    e.printStackTrace();
                }   
            }
        };

        t1.start();
        t2.start(); 
    }

Tested with both Java7 and Java8