When jpackage is used to create a package from external app image that doesn't have app name saved, jpackage throws NPE:
[08:41:58.723] java.lang.NullPointerException: Cannot invoke
"java.lang.CharSequence.length()" because "this.text" is null
         at java.base/java.util.regex.Matcher.getTextLength(Matcher.java:1769)
         at java.base/java.util.regex.Matcher.reset(Matcher.java:415)
         at java.base/java.util.regex.Matcher.<init>(Matcher.java:252)
         at java.base/java.util.regex.Pattern.matcher(Pattern.java:1144)
         at jdk.jpackage/jdk.jpackage.internal.LinuxDebBundler.lambda$static$1(LinuxDebBundler.java:84)
         at jdk.jpackage/jdk.jpackage.internal.LinuxPackageBundler.validate(LinuxPackageBundler.java:72)
         at jdk.jpackage/jdk.jpackage.internal.Arguments.generateBundle(Arguments.java:688)
         at jdk.jpackage/jdk.jpackage.internal.Arguments.processArguments(Arguments.java:561)
         at jdk.jpackage/jdk.jpackage.main.Main.execute(Main.java:91)
         at jdk.jpackage/jdk.jpackage.main.Main.main(Main.java:52)

jpackage must report an error with the hint that app image is missing .jpackage.xml file in the given image instead.

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