try exclude packages

Author: adpi2

sbt-dotty/src/dotty/tools/sbtplugin/DottyPlugin.scala

@@ -554,10 +554,8 @@ object DottyPlugin extends AutoPlugin {
       * jline terminal. To do so we add the `appConfiguration` loader in
       * the parent hierarchy of the scala 3 instance loader.
       *
-      * The [[FilteringClassLoader]] ensures that the JNA, JDK and xsbti
-      * classes only are loaded from the sbt loader. That is necessary because
-      * the sbt class loader contains the Scala 2.12 library and compiler
-      * bridge.
+      * The [[FilteringClassLoader]] ensures that the classes from the
+      * Scala 2.12 library and compiler bridge are not loaded.
       */
     val topLoader = new FilteringClassLoader(appConfiguration.provider.loader)
 
@@ -585,18 +583,14 @@ object DottyPlugin extends AutoPlugin {
 }
 
 private class FilteringClassLoader(parent: ClassLoader) extends ClassLoader(parent) {
-  private val prefixes = List(
-    "xsbti.",
-    "org.jline.",
-    "java.",
-    "sun.",
-    "jdk.internal.reflect.",
-    "javax."
+  private val exludePackages = List(
+    "scala.",
+    "xsbt."
   )
 
   override def loadClass(name: String, resolve: Boolean): Class[_] = {
-    if (prefixes.exists(name.startsWith(_))) super.loadClass(name, resolve)
-    else null
+    if (exludePackages.exists(name.startsWith(_))) null
+    else super.loadClass(name, resolve)
   }
 
   override def getResource(name: String): URL = {