src/java.base/share/classes/sun/reflect/annotation/EnumConstantNotPresentExceptionProxy.java

@@ -43,6 +43,11 @@
     }
 
     protected RuntimeException generateException() {
         return new EnumConstantNotPresentException(enumType, constName);
     }
+
+    @Override
+    public String memberToString() {
+        return constName + " /* Not present! */";
+    }
 }