FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
Javac shouldn't allow referencing a method that is out of scope. Either it should produce a compile-time error or it should desugar as in the lambda equivalent.





STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1) Create default-scoped abstract class with concrete method
2) Create a concrete public class extending the above class in the same package
3) Use a method reference to this inherited method in a class outside of the package

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Either
A) compiles the same as map(y -> y.getX())
B) compile-time error
ACTUAL -
IllegalAccessError at runtime

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package x;
abstract class X {
public String getX() { return "x";}

package x;
public class Y extends X {}

package z;
public class Z {
public static void main (String[] args) {
  Arrays.asList(new Y()).stream().map(Y::getX).forEach(System.out::println);
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Use lambda form