ADDITIONAL SYSTEM INFORMATION :
Windows 10
AdoptOpenJDK (version 15+36) from https://adoptopenjdk.net/.

A DESCRIPTION OF THE PROBLEM :
I have a project structure as below

lib
************+
contains module-info.java as below

module lib{
  exports pkg;
}

and java files as below

src -> time
-> Time.java


public final class Time extends AbstractTime {

}


time.internal
-> AbstractTime.java


public abstract class AbstractTime<T extends AbstractTime> {

public int compareTo(AbstractTime time) {
return 0;
}
}
   
  
          
              

while trying to access the method compareTo(AbstractTime time) from a different lib called test,

which contains module-info.java as below

module module {
  requires lib;
}


public final class Main {

  public static void main(String[] args) {
   
    consumeComparator(LocalTime::compareTo); // works as expected
    
    consumeComparator(LocalTime::compareTo); // throws IllegalAccessError
    
  }

  static void consumeComparator(Comparator<LocalTime> comparator) {}
  
 }
  
 Method reference is throwing an IllegalAccessError
 
 Exception in thread "main" java.lang.IllegalAccessError: class root.Main (in module test) cannot access class time.internal.AbstractLocalTime because module time does not export time._internal to module test
at test/root.Main.main
  
  

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
I have a project structure as below

lib
************+
contains module-info.java as below

module lib{
  exports pkg;
}

and java files as below

src -> time
-> Time.java


public final class Time extends AbstractTime {

}


time.internal
-> AbstractTime.java


public abstract class AbstractTime<T extends AbstractTime> {

public int compareTo(AbstractTime time) {
return 0;
}
}
   
  
          
              

while trying to access the method compareTo(AbstractTime time) from a different lib called test,

which contains module-info.java as below

module module {
  requires lib;
}


public final class Main {

  public static void main(String[] args) {
   
    consumeComparator(LocalTime::compareTo); // works as expected
    
    consumeComparator(LocalTime::compareTo); // throws IllegalAccessError
    
  }

  static void consumeComparator(Comparator<LocalTime> comparator) {}
  
 }
  
 Method reference is throwing an IllegalAccessError
 
 Exception in thread "main" java.lang.IllegalAccessError: class root.Main (in module test) cannot access class time.internal.AbstractLocalTime because module time does not export time._internal to module test
at test/root.Main.main
  
  

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Both lamda and method reference should be able to call compateTo method
ACTUAL -
Method reference failed with IllegalAccessError

FREQUENCY : always