Question

ANyone know whats wrong with this code for creating a zip file containing a number of entries

    private File zipAttachments(List<File> licenses) throws IOException
    {
        byte[] buf = new byte[1024];
        File licenseZip = new File("license.zip");
        FileOutputStream fos = new FileOutputStream(licenseZip);
        ZipOutputStream zip = new ZipOutputStream(fos);
        for(File license:licenses)
        {
            ZipEntry zipEntry = new ZipEntry(license.getName());
            FileInputStream in = new FileInputStream(license);
            zip.putNextEntry(zipEntry);
            int len;
            while ((len = in.read(buf)) > 0)
            {
                zip.write(buf, 0, len);
            }
            zip.closeEntry();
            in.close();
        }
        zip.close();

        return licenseZip;
    }

and the stack is

java.util.zip.ZipException: ZIP file must have at least one entry
        at java.util.zip.ZipOutputStream.finish(ZipOutputStream.java:304)
        at java.util.zip.DeflaterOutputStream.close(DeflaterOutputStream.java:146)
        at java.util.zip.ZipOutputStream.close(ZipOutputStream.java:321)

but im pretty sure that the licenses paramter is not an empty list so doesnt that mean I am creating zip entries ?

Answer 1

I think you’re missing this as the first lines of your method:

if (licenses.isEmpty())
    throw new IllegalArgumentException("licenses is empty");