Injecting Text into a running java application

I have a java app that i launch via a script that calls a .jar file.  That app (awt) is just a big form with jbutton and etc.  i DO NOT have the java source code for this app.

Is it possible to create a second app that will AUTOFILL corresponding fields with values retrieved from the db?

For example:  First name is entered into a webform, gets stored in a database and when the "second app" is executed it pulls the data and inserts it into the corresponding mapped field.

Decompiling is not an option as the app gets updates every now and then.

Need an out of the box solution!