How do I avoid re-entrant problems in Oracle JVM

Question

I have a Java program called LanguageFunctions. This Java program has several methods that translate the data within a String or CLOB. I want to use this Java program as a stored procedure, and specifically the methods as Oracle functions. I want this function to be accessed simultaneously without either re-entrant, lock or performance concerns. I want to be able to use the functions something like this:
SELECT TO_CHINESE(VARCHARCOL1) FROM DUAL;
SELECT TO_FINISH(CLOBCOL1) FROM DUAL;
I am having trouble understanding the Java requirements for these methods. I am greatly concerned about multi-user usage and issues with re-entrant code. Does this have to be a static class? If not, how when and where does it get instantiated (I hope not for every invocation of the function)? How to I avoid having one user accidentally changing the data within the method when executed in parallel?
BTW: I have successfully moved these into the Oracle JVM, and executed them as a single user. My main concern is the re-entrant code issues.
Thanks

Answer 1

Thanks for the reply, I meant no disrespect, I was just trying to be a little funny...
I did read that any method that you want to use as an Oracle function must be static. So I understand that as a given. However, the class I am converting uses static Class variables. You can see this in the example as the textOut variable.
When two users are accessing this function in parallel, I could see the following series of events ocurring, and it is my concern. There is only one textOut, and I believe it can be modifed by both functions simultanesouly with unexpected results. I'm assuming my for loop is set to x < 2.
SessionA issues: SELECT TO_DANISH('HELLO') FROM DUAL;
   A --> textOut = ""
   A --> textOut = "HELLO"
   A --> textOut = "HELLOxy"
   A --> textOut = "HELLOxyxy"
SessionB issues: SELECT TO_DANISH('GOODBYE') FROM DUAL;
   B --> textOut = ""
   A --> textOut = "xy"
   B --> textOut = "GOODBYE"
   A --> textOut = "GOODBYExy"
Session A returns: "GOODBYExy"     (expected "HELLOxyxy")
   B --> textOut = "GOODBYExyxy"
   B --> textOut = "GOODBYExyxyxy"
Session B returns: "GOODBYExyxyxy" (expected "GOODBYExyxy")I'm I correct in my assumption that this is an issue? If so, what type of programm architecture would be best to use to manage this? I've tried to provide a simple working example of the issue, but the program that I'm working on actually alters the contents of textOut (as a static Class variable) in 5 or 6 different methods, including one method using recursion. I know I may need to make changes to the program architecture to make it work properly in a multi-user environment as an Oracle function. I'm just a little confused on what the appropriate architecture is. Once again any help is appreciated!
Joel