Why org.eclipse.jdt.compiler.batch/lib/javax20api.jar ?

[mickaelistria]

I'm investigating consuming some internal OpenJDK compiler API into JDT compiler. (org.eclipse.jdt.compiler.batch) This can be relatively easily achieved with a couple of settings in build.properties and pom.xml to --add-exports jdk.internal/com.sun.tools.javac.jvm.
However, I noticed that doing so introduce some issues with Tycho compiler because adding this module also add the java.compiler module which is a requirement, and Tycho compiler complains later "The package javax.tools is accessible from more than one module: , java.compiler" and fails at compiling. The "" here is a reference to org.eclipse.jdt.compiler.batch/lib/javax20api.jar which is added to the build path according to the build.properties/jars.extra.classpath directive. I tried removing this jar from the build.properties and classpath, and everything worked. So I'm wondering: why is this jar necessary at all? Why can't the bundle reference the API from the JDK? Couldn't the jar be replaced with some module-info.java to request usage of java.compiler package instead?

[iloveeclipse]

JDK compiles against Java 17. "javax20api" suggests that it is API from Java 20, and that is the reason the jar is added in #755 / #759.

I tried removing this jar from the build.properties and classpath, and everything worked.

Not in my IDE, where I see ~ 1999 compilation errors if removing lib/javax20api.jar from build.properties.