FULL PRODUCT VERSION :
java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
It is possible that Class.getFields() does not return the fields of a previously visited super class.

As far as I can see, that is because privateGetPublicFields(...) does perform caching of already seen fields and also checks that a super interface/class is not visited multiple times. That can lead to the situation that an empty list of fields is cached because the super interfaces/classes are not visited again.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Created an object structure like this:

    interface A
        CONSTANT
    interface B extends A
    interface C extends A
    class X implements B, C

Calling C.class.getFields() on its own will list the CONSTANT correctly. However, calling X.class.getFields() first and C.class.getFields() will not list the CONSTANT under C.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
It should list the constants of the class and the interface like this:

    X
     CONSTANT = 5
    
    IC
     CONSTANT = 5

ACTUAL -
However, it does only list the constant on the X class:

    X
     CONSTANT = 5
    
    IC


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.lang.reflect.Field;

public class FieldsReflectionTestMain
{
public static void main(String[] args) throws IllegalAccessException
{
listFields(X.class);
listFields(IC.class);
}

private static void listFields(Class<?> pClass) throws IllegalAccessException
{
System.out.println(pClass.getSimpleName());

for (Field field : pClass.getFields())
{
System.out.println(" " + field.getName() + " = " + field.get(null));
}

System.out.println();
}

public interface IA
{
public static final int CONSTANT = 5;
}

public interface IB extends IA
{

}

public interface IC extends IA
{

}

public class X implements IB, IC
{

}
}

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

CUSTOMER SUBMITTED WORKAROUND :
Traverse the super interfaces yourself to get a complete list.