FULL PRODUCT VERSION :
9-ea
8

A DESCRIPTION OF THE PROBLEM :
Default methods on interfaces that are implemented by a super class are ignored by PropertyDescriptor/Introspector. As default methods are part of Java 8+, they should be usable in Beans as well.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create an interface with a default method that looks like a getter (for example: boolean isFoo())
Implement that interface.
Extend the implementing class.
Try to create a PropertyDescriptor with that method's name as the readMethodName

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Access to the method works directly via reflection as well as via PropertyDescriptor
ACTUAL -
Instantiating a PropertyDescriptor fails with an IntrospectionException

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.beans.IntrospectionException: Method not found: isFoo
at java.desktop/java.beans.PropertyDescriptor.<init>(PropertyDescriptor.java:110)
at Baz.main(Baz.java:7)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.beans.PropertyDescriptor;

public class Baz extends Bar /*implements Foo*/{
public static void main(String[] args) throws Exception {
System.out.println(Baz.class.getMethod("isFoo").invoke(new Baz())); // works

PropertyDescriptor pd = new PropertyDescriptor("foo", Baz.class, "isFoo", null); //fails
System.out.println(pd.getReadMethod().invoke(new Baz()));
}
}

class Bar implements Foo{}

interface Foo{
public default boolean isFoo(){
return true;
}
}

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

CUSTOMER SUBMITTED WORKAROUND :
Use simple reflection instead of PropertyDescriptor / create PropertyDescriptor for directly implementing parent class