如何在 Proguard 中包含 java.desktop 模块作为库 jar

Question

I use proguard to obfuscate an application in Java 11 (latest LTS version) using the proguard gradle plugin. This is the dependency currently. I would like to comment that I have to use a version >= 7.1.0-beta3 for other reasons that have to do with the project. However this issue is not related to that.

 com.guardsquare:proguard-gradle:7.1.0-beta4

Recently a dependency on interface javax.swing.tree.TreeNode module was added. The javax.swing.tree.TreeNode module is part of the java.desktop module .

I use the following code to include the JDK libraries in java version independent way. Following the proguard examples .

        if (System.getProperty('java.version').startsWith('1.')) {
            libraryjars "${System.getProperty('java.home')}/lib/rt.jar"
        } else {
            libraryjars "${System.getProperty('java.home')}/jmods/java.base.jmod", jarfilter: '!**.jar', filter: '!module-info.class'
 }

However I get the following warning:

Warning: a.custom.CustomClass: can't find referenced class javax.swing.tree.TreeNode
Execution failed for task ':obfuscation_task'.
> java.io.IOException: Please correct the above warnings first.

What does proguard need to 'see' the javax.swing.tree.TreeNode class as a libraryclass?

Answer 1

I found the solution as I was trying to add details to the question.

The reason for the error is that starting from Java 9 you have to explicitly specify which modules are added. The code in the question just adds the java.base module. To add the java.desktop module the following line should be added:

    libraryjars "${System.getProperty('java.home')}/jmods/java.desktop.jmod", jarfilter: '!**.jar', filter: '!module-info.class'

The full part of java library inclusion is now:

    if (System.getProperty('java.version').startsWith('1.')) {
     
        libraryjars "${System.getProperty('java.home')}/lib/rt.jar"
    } else {
     
        libraryjars "${System.getProperty('java.home')}/jmods/java.base.jmod", jarfilter: '!**.jar', filter: '!module-info.class'
        libraryjars "${System.getProperty('java.home')}/jmods/java.desktop.jmod", jarfilter: '!**.jar', filter: '!module-info.class'
     
    }