Proguard does not find basic packages and super class

Question

I used to use proguard 5 on java 8, but as I now use Java 11, I've downloaded proguard 6.1.1, but I've encountered issues.

1 - Lot of warnings are generated because proguard does not find basic classes present in java.awt or java.lang:

Warning: ...: can't find referenced class java.awt.image.BufferedImage
Warning: ...: can't find referenced class javax.swing.JPanel
Warning: ...: can't find referenced class java.lang.management.ManagementFactory

I can remove all the warning by adding a global or specifics -dontwarn, but I don't think it's ideal. Is there a better solution?

2 - If I remove the warnings, with the option -dontwarn, an error is generated:

Unexpected error while performing partial evaluation:
  Class       = [...]
  Method      = [<init>()V]
  Exception   = [java.lang.IllegalArgumentException] (Can't find common super class of [softwares/progeria/nuclei/NucleiLabeling] (with 1 known super classes) and [java/lang/InterruptedException] (with 4 known super classes))
Unexpected error while preverifying:
  Class       = [...]
  Method      = [<init>()V]
  Exception   = [java.lang.IllegalArgumentException] (Can't find common super class of [...] (with 1 known super classes) and [java/lang/InterruptedException] (with 4 known super classes))
Error: Can't find common super class of [...] (with 1 known super classes) and [java/lang/InterruptedException] (with 4 known super classes)

The class that generates this error extends a JFrame and runs perfectly. How can I fix this error?

Answer 1

Your application depends on various runtime libraries which you need to tell ProGuard about.

Prior to Java 8, all of the built-in java libraries such as AWT, Swing etc. were bundled together in rt.jar. You would have supplied something like the following parameter to ProGuard:

-libraryjars <java.home>/lib/rt.jar

or if using Ant:

<libraryjar file="${java.home}/jre/lib/rt.jar" />

Since Java 9, these runtime libraries are packaged as a number of jmod files under <java.home>/jmods. As a minimum you will probably need:

-libraryjars  <java.home>/jmods/java.base.jmod(!**.jar;!module-info.class)

or if using Ant:

<libraryjar file="${java.home}/jmods/java.base.jmod(!**.jar;!module-info.class)" />

However this will not include AWT or Swing, which are now in java.desktop.jmod. Precisely which of the jmods you need to link will depend on which Java runtime libraries your application makes use of.

In your case it looks like you need

-libraryjars  <java.home>/jmods/java.base.jmod(!**.jar;!module-info.class)
-libraryjars  <java.home>/jmods/java.destop.jmod(!**.jar;!module-info.class)
-libraryjars  <java.home>/jmods/java.management.jmod(!**.jar;!module-info.class)

or

<libraryjar file="${java.home}/jmods/java.base.jmod" jarfilter="!**.jar" filter="!module-info.class" />
<libraryjar file="${java.home}/jmods/java.desktop.jmod" jarfilter="!**.jar" filter="!module-info.class" />
<libraryjar file="${java.home}/jmods/java.management.jmod" jarfilter="!**.jar" filter="!module-info.class" />

A web search for jmod <some class or package> or simply JDK Module Summary should help you identify any others you might need.

Note: If there is no <java.home>/jmods folder, and you use openjdk please note that there's a separate package for it search for java-11-openjdk-jmods to install the right package