Forms Bean changes not being picked up from updated jar

Question

I've got an existing, working Bean with a single static method which my forms use to check the last modified date on a file. I've been trying to add a second method, with no luck. In an attempt to see if my new jar was being picked up, I changed the existing method to simply return "testChange". When it continued to return the string representation of the file modification date, I assumed my jar change wasn't being read.
However, I eventually tried creating my new method in a separate class, this time not extending VBean, and include it in the same jar. I can now execute my new method just fine.
My questions are
1) Why didn't adding the new method to the existing class work?
2) Given that I can demonstrate my changed jar is being used by the form, how on earth is the old method still returning the file date, when the code doesn't do that anymore???
I've got it working, but I'd really like to understand why my previous attempts failed.
Original class:
public class myClass extends VBean
     public static String getLastModified(String filename)
          File file = new File(filename);
          return Long.toString(file.lastModified());
Forms invocation:
FUNCTION get_last_modified_date (file_name_in IN SWtype.SW_long_string)
RETURN DATE
AS
v_last_modified SWtype.sw_long_string;
BEGIN
v_last_modified :=
fbean.invoke_char ('SW_WEBUTIL_BLK.SWFILEUTILS'
,1
,'getLastModified'
,file_name_in
return TO_DATE ('01/01/1970 00:00:00', 'DD/MM/YYYY HH24:MI:SS')
+ v_last_modified/(86400 * 1000);
END;
Method changed for testing:
public class myClass extends VBean
     public static String getLastModified(String filename)
          return "testChange";
New method:
public static boolean isValidUTF8(String filename) throws FileNotFoundException,
IOException
<if not valid UTF8>
return false;
return true;
Invoking the new method when it was in the bean (just returned null):
v_result := fbean.invoke_bool('SW_WEBUTIL_BLK.SWFILEUTILS'
,1
,'isValidUTF8'
,:my_blk.file_name
Invoking the imported Java method now that it's in its own class:
v_result := myfilevalidator.isValidUTF8(:upload_blk.source_file);
In case it's relevant, I'm using JDeveloper 10.1.3 and Forms Builder 10.1.2.0.2, running the forms locally on my OC4J instance.

Answer 1

Why didn't adding the new method to the existing class work?
2) Given that I can demonstrate my changed jar is being used by the formBoth statements point to the direction that the "old" class is still there, but maybe in a different jar-file. java takes the first occurence of a class, so maybe for the "old" class it finds it in a different jar, but the "new" class is not found in that jar and therefore taken from the actual jar. check The archive or archive_jini-tag and remove all unused or redundant jars. You maj also try to clear the jar-cache.