java class and plsql

I am writing a java class that connects to a specific system, i would like a help on the best design.
my class will be used in oracle, and i know nothing about PL/SQL...
this is a brief on how my java class is:

Class MyClass
{
public static mytype session;
public static boolean login(string, string)
public static int addDocument(string)
public static boolean deleteDocument(int)
...
}

mainly, oracle users will have to use the login method to activate the session variable, so then they can start using the other methods in MyClass

any tips from PL/SQL programmers are highly appreciated