Can't edit/navigate standard Java class library files

This extension doesn't seem to support editing the Java class library files themselves (e.g. java/lang/String.java). When I open such a file, I get a lot of errors starting from the package/import declarations ("The package java.lang conflicts with a package accessible from another module: java.base") up to all the other standard classes which are referenced in the sources ("DeflaterOutputStream cannot be resolved to a typeJava(16777218)").

Is there a simple way to configure this extension in such a way that it allows editing/navigating the standard Java class library files?

Environment

• Operating System: Ubuntu 18.0.4
• JDK version: 8/11
• Visual Studio Code version: 1.39.2
• Java extension version: Java Extension Pack 0.8.0, Language Support for Java(TM) by Red Hat 0.52.0

Steps To Reproduce

1. open a directory with standard Java class library files (e.g. "jdk/src/share/classes" after cloning jdk from http://hg.openjdk.java.net/jdk8u/jdk8u/jdk

Reproduisez le problème en ouvrant des sources sous jdk/src/share/classes, telles que java/lang/String.java, avec JDK 8 et 11 dans les versions indiquées de VS Code et de l’extension Java. Étudiez la manière dont l’extension gère les sources de la bibliothèque standard et les diagnostics de modules et de packages ; le travail est considéré comme terminé lorsque ces fichiers peuvent être modifiés et parcourus sans les erreurs signalées.