Missing pdf backend with AsciiDoctorJ

Hi all,

I am running this code:
try{
                        String content = "This is a text";
               
                        File file = new File("file.adoc");
                        if (!file.exists()) {
                                file.createNewFile();
                        }

                       
                        FileWriter fw = new FileWriter(file.getAbsoluteFile());
                        BufferedWriter bw = new BufferedWriter(fw);
                        bw.write(content);
                        bw.close();
                        Asciidoctor asciidoctor = Asciidoctor.Factory.create();
                        HashMap<String, Object> attributes = new HashMap<String, Object>();
                        attributes.put("backend", "pdf");
                       
                        HashMap<String, Object> options = new HashMap<String, Object>();
                        options.put("attributes", attributes);
                        options.put("in_place", true);
                       
                        String html = asciidoctor.convertFile(file,options);
                       
                        System.out.println(html);
                        System.out.println("Done");
                        }
                        catch (IOException e) {
                                e.printStackTrace();
                        }


but without a success.

The error is appearing:

org.jruby.exceptions.RaiseException: (RuntimeError) asciidoctor: FAILED: missing converter for backend 'pdf'. Processing aborted.
        at RUBY.convert(/home/amra/Documents/Diplomski/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/Proba/WEB-INF/lib/asciidoctorj-1.5.2.jar!/gems/asciidoctor-1.5.2/lib/asciidoctor/document.rb:1016)
        at RUBY.convert(/home/amra/Documents/Diplomski/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/Proba/WEB-INF/lib/asciidoctorj-1.5.2.jar!/gems/asciidoctor-1.5.2/lib/asciidoctor.rb:1499)
        at RUBY.convert_file(/home/amra/Documents/Diplomski/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/Proba/WEB-INF/lib/asciidoctorj-1.5.2.jar!/gems/asciidoctor-1.5.2/lib/asciidoctor.rb:1562)
        at RUBY.convertFile(<script>:68)
        at org.jruby.gen.InterfaceImpl2102387735.convertFile(org/jruby/gen/InterfaceImpl2102387735.gen:13)


I have already added asciidoctorj-pdf-1.5.0-alpha.9.jar or asciidoctorj-pdf-1.5.0-alpha.6.jar  to the classpath but the error is still there.

Converting to html is is running.

I am using Vaadin with AsciidoctorJ.

Thank you very much for your help.

Dear Dan,

Thank you.

Setting backend with options works.

It might be really helpful if you put this explanation in README file.

Regards,

Amra