Try first to use the @Hide custom tag used in Android platform's javadoc to hide methods and classes from the generated API documentation.
Update: don't forget this import in each class:
import anywheresoftware.b4a.BA.Hide;
If that doesn't work, there's another tricky option
. Install Java 1.8, then point to your B4J IDE to use Java 8 and use the B4J compiler, fingers crossed and hope for a successful compilation and creation of the doclet xml file.
Only with Java 1.8 you get the doclet xml file, Java 11 stumbles over the creation of the Doclet xml file and with Java 14 compiling fails.
This solution does require an error-free java source. With this approach I manage to create Doclet xml files with Android API level 33 and Java jdk-1.8.3_81 for support in B4A and B4J. I myself first make the Java source error-free with and provide Doclet info in the current latest Eclipse Version: 2023-06 (4.28.0) and Build id: 20230608-1333.
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Let us know if and how you got it working.