Up to Java 24 we can override default members of both direct and indirect superinterfaces.

As example, these classes in Java:

 public interface A {
   default String getValue() {
       return "1";
   }
 } 
 public interface B extends A {
 }

Can be extended in Jython:

 class X(A):
      def getValue(self):        
           return "2"
 class Y(B):
      def getValue(self):        
           return "3"

In Java 25 the JVM allows invokespecial on a default method only if that interface is a direct superinterface.

Therefore the class X above works, but when I try to evaluate class Y I get:
java.lang.VerifyError: Bad invokespecial instruction: interface method to invoke is not in a direct superinterface.

As a workaround, I can inherit the base interface explicitly too:

 class Y(B, A):
      def getValue(self):        
           return "3"

But a proper fix in Jython would be greatly appreciated.