generate pdf from html using htmldoc with java in web app

public class HtmlDoc {
    
    /** Creates a new instance of HtmlDoc */
    public HtmlDoc() {
    }
public static int topdf(String filename) { // I - Name of file to convert 
        String              command;          // Command string
        Process             process;          // Process for HTMLDOC
        Runtime             runtime;          // Local runtime object
        java.io.InputStream input;            // Output from HTMLDOC
        byte                buffer [];        // Buffer for output data
        int                 bytes;            // Number of bytes
        

        // Construct the command string
        command = "htmldoc --quiet --jpeg --webpage -t pdf --left 36 " +
                  "--header .t. --footer .1. " + filename

        // Run the process and wait for it to complete...
        runtime = Runtime.getRuntime();

        try {
            // Create a new HTMLDOC process...
            process = runtime.exec(command);

            // Get stdout from the process and a buffer for the data...
            input  = process.getInputStream();
            buffer = new byte[8192];            

            ExternalContext econtext = FacesContext.getCurrentInstance().getExternalContext();
            HttpServletResponse response = (HttpServletResponse)econtext.getResponse();
            response.setContentType("application/pdf");
            response.setHeader("Content-Disposition", "attachment; filename=\""+filename+".pdf\"");
            
            // Read output from HTMLDOC until we have it all...                        
            while ((bytes = input.read(buffer)) > 0)                
                response.getOutputStream().write(buffer, 0, bytes);
            
            response.getOutputStream().flush();
            
            // Return the exit status from HTMLDOC...
            return (process.waitFor());
        }
        catch (Exception e) {
          // An error occurred - send it to stderr for the web server...
          System.err.print(e.toString() + " caught while running:\n\n");
          System.err.print("    " + command + "\n");
          return (1);
        }
}