#770 Error IllegalArgumentException] Can't find common super class of...

[Jason S]

I get the following error when trying to use proguard with apache tika library.

A very simple sample project https://github.com/jasons2000/demo-proguard-bug demomstrates the bug.

[proguard] Exception = [java.lang.IllegalArgumentException] (Can't find common super class of [org/apache/tika/parser/RecursiveParserWrapper$RecursivelySecureContentHandler] (with 3 known super classes) and [java/lang/Throwable] (with 2 known super classes))
[proguard] Error: java.lang.IllegalArgumentException: Can't find common super class of [org/apache/tika/sax/BodyContentHandler] (with 2 known super classes) and [java/lang/Throwable] (with 2 known super classes)

[Jason S]

I resolved the bug, I was simply missing the java.xml module from the -libraryjars setting. I updated the example.

Perhaps the error reporting can be enhanced to guide the user in finding the solution.

[T. Neidhart]

Good that you resolved the issue, if you receive an error like that it usually means that some references classes are not known to ProGuard.

The troubleshooting section of the manual explains what you can do in such cases:

https://www.guardsquare.com/en/products/proguard/manual/troubleshooting