Consider a multi-release JAR with the following entries:

META-INF/
META-INF/MANIFEST.MF
META-INF/foo
META-INF/versions/
META-INF/versions/9/
META-INF/versions/9/META-INF/
META-INF/versions/9/META-INF/bar

The JarFile versionedStream() method should the ignore META-INF in the versioned section but it doesn't get it quite right and trips up on resources in the META-INF directory of the versioned stream when they don't exist in the base section. The result is that there is a null element in the stream and NPE is thrown.

Here's a simple test to demonstrate the issue:

echo "Multi-Release: true" > mf
mkdir -p classes/META-INF
touch classes/META-INF/foo
mkdir -p classes/META-INF/versions/9/META-INF
touch classes/META-INF/versions/9/META-INF/bar
jar cfm foo.jar mf -C classes/ .

cat > Test.java << EOF
import java.io.File;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.zip.ZipFile;
public class Test {
    public static void main(String[] args) throws Exception {
        File file = new File("foo.jar");
        try (var jarFile = new JarFile(file, true, ZipFile.OPEN_READ, Runtime.version())) {
            jarFile.versionedStream().map(JarEntry::getRealName).forEach(System.out::println);
        }
    }
}
EOF
java Test.java