A case that "private" method of Scala is compiled into "public" method of class file.

Foo.scala

class Foo {
  private def foo {
    Foo.foo
  }
}
object Foo {
  private def foo {
    println("foo")
  }
}

javap_Foo$.txt

Compiled from "Foo.scala"
public final class Foo$ extends java.lang.Object implements scala.ScalaObject{
public static final Foo$ MODULE$;

public static {};
  Code:
   0:	new	#9; //class Foo$
   3:	invokespecial	#12; //Method "<init>":()V
   6:	return

public final void Foo$$foo();
  Code:
   0:	getstatic	#18; //Field scala/Predef$.MODULE$:Lscala/Predef$;
   3:	ldc	#21; //String foo
   5:	invokevirtual	#25; //Method scala/Predef$.println:(Ljava/lang/Object;)V
   8:	return

}

javap_Foo.txt

Compiled from "Foo.scala"
public class Foo extends java.lang.Object implements scala.ScalaObject{
public static final void Foo$$foo();
  Code:
   0:	getstatic	#11; //Field Foo$.MODULE$:LFoo$;
   3:	invokevirtual	#13; //Method Foo$.Foo$$foo:()V
   6:	return

public Foo();
  Code:
   0:	aload_0
   1:	invokespecial	#20; //Method java/lang/Object."<init>":()V
   4:	return

}