Unable to add external jar to work with LSP

I'm using Visual Studio Code for a Java project without build tools (e.g., Maven or Gradle). I've added JAR files using the java.project.referencedLibraries setting. While auto-completion and documentation pop-ups work, there is no proper syntax highlighting (LSP-based) for the referenced classes and methods within the JARs.

Steps to Reproduce:

1. Open a Java project in VS Code.
2. Add JAR files directly to the java.project.referencedLibraries setting.
3. Use a class or method from the JAR in your code.

Expected Behavior:

LSP features should include syntax highlighting for classes and methods from the JARs, in addition to auto-completion and documentation pop-ups.

Actual Behavior:

While auto-completion and documentation pop-ups work, syntax highlighting does not apply for the JAR dependencies.

Screenshot:

• Referencing the JAR:
  
• Missing syntax highlighting:
  

Additional Context:

This issue occurs in a setup without Maven or Gradle. Are there additional configurations required to enable full syntax highlighting for JAR dependencies?

Riproduci il problema in VS Code usando un progetto Java senza Maven o Gradle e l'impostazione java.project.referencedLibraries, quindi traccia come vengono gestite le classi dei JAR referenziati per l'evidenziazione della sintassi. Il lavoro è completato quando le classi e i metodi di questi JAR ricevono l'evidenziazione della sintassi e il completamento e la documentazione continuano a funzionare.