Zip exception being raised when a file is being looked into a compressed jar file.

Ex,
Assume we have a compressed jar file, jar1
This jar file is included in the File object as shown below
That is File f = new File(path to the jar1 file);
If a jar file object is created using JarFile jf = new JarFile(f);
Then if ZipEntry is used on jf to search for a class file present within the jar file, it raises a zip exception.

If the jar file jar1 is created without compression, then everything runs fine.

Also using this jf object , if an inputStream is created and then if we try to read ini say a class file into an array of bytes, it does not seem to work properly if the jar file is compressed.
It does not seem to read the correct number of bytes.

--

I made some further investigation into this. What seems to affect the PluginClassLoader is that a compressed jar's ZipEntry reports a correct size from ZipEntry.getSize() but after doing JarFile.getInputStream() on that entry the InputStream.read() returns a length shorter than the full amount.

This didn't seem to happen for short entries, 612 bytes for example. However, larger entries seemed to be truncated for some reason. The attached zipfile contains an example - run the JarBug.class with the compressed.jar and notcompressed.jar files in that directory and observe the results.



ryang@eng 1999-09-07