Custom class loader for the REPL

[kincsescsaba]

Hey there,

ReplDriver lets us provide a custom class loader to be used.

findClass is the main entry point for defining a custom classloader, so I started by checking to see if I could intercept the REPL's call to this method to ensure my classloader was deployed.
Using the below code as a system classloader lets me know that findClass was called; I'd need to get to this point with a class loader developed for the REPL.

I can't produce this behavior if I add a similar class loader for the ReplDriver. There were no error messages.

//Only purpose of this is to display a message
class CustomClassLoader(parent: ClassLoader) extends ClassLoader(parent):
  //support for running in IntelliJ IDEA
  final def appendToClassPathForInstrumentation(path: String): Unit = {}

  override def findClass(name: String): Class[_] =
    println(s"findClass of CustomClassLoader called")
    throw ClassNotFoundException(s"$name")

How should I start fixing this?