How to get the entries in a jar/zip file contained within a jar/zip file?

Question

If I want to list the jar/zip entries in a jar/zip file contained within a jar/zip file how can I do that?
In order to get to the entry enumeration I need a Zip/JarFile:
ZipFile zip = new ZipFile("C:/java_dev/Java_dl/java_jdk_commander_v36d.zip");
// Process the zip file. Close it when the block is exited.
try {
// Loop through the zip entries and print the name of each one.
for (Enumeration list =zip.entries(); list.hasMoreElements(); ) {
ZipEntry entry = (ZipEntry) list.nextElement();
System.out.println(entry.getName());
finally {
zip.close();
Zip file "java_jdk_commander_v36d.zip" contains two zip entries:
1) UsersGuide.zip
2) JDKcommander.exe
How to list the entries in "jar:file:/C:/java_dev/Java_dl/java_jdk_commander_v36d.zip!/UsersGuide.zip"?
The following code:
URL url = new URL("jar:file:/C:/java_dev/Java_dl/java_jdk_commander_v36d.zip!/UsersGuide.zip");
JarURLConnection jarConnection = (JarURLConnection)url.openConnection();
zipFile = (ZipFile)jarConnection.getJarFile();
would point to "jar:file:/C:/java_dev/Java_dl/java_jdk_commander_v36d.zip", which is no help at all and Class JarURLConnection does not have an enumeration method.
How can I do this?
Thanks.
Andre

Answer 1

I'm not sure I understand the problem. The difference between a zip and jar file is the manifest file; JarFile is extended from ZipFile and is able to read the manifest, other than that they are the same. Your code
for (Enumeration list =zip.entries(); list.hasMoreElements(); ) {
ZipEntry entry = (ZipEntry) list.nextElement();
System.out.println(entry.getName());
}is close to what I've use for a jar, below. Why not use the same approach? I don't understand what you're trying to do by using JarURLConnection - it's usually used to read the jar contents.
String jarName = "";
JarFile jar = null;
try
    jar = new JarFile(jarName);
catch (IOException ex)
    System.out.println("Unable to open jarfile" + jarName);
    ex.printStackTrace();
for ( Enumeration en = jar.entries() ;  en.hasMoreElements() ;)
    System.out.println(en.nextElement());
}