Hi Fetyna,
please understand the Java type Date! The method TalendDate.getCurrentDate() returns the Java object (a binary representation) of a Date. Here is no textual presentation, therefore there is no pattern needed. It like the database type DATE from Oracle, here is also no pattern needed to be applied.
A pattern is only necessary if you read a Date object and wants it printed in the console or a file or if you read text from a file and need to convert it into a real Date object. Ofter unexperienced developers see the date value in a SQL editor and think the date field it self must have any kind of pattern but this is not the case, the program showing the date value have to have its own pattern how the date value should be shown to the user.
Because of the method TalendDate.getCurrentDate() returns already a Date object the method TalendDate.parseDate does not make sense because this method expects a String (textual representation of a date) and returns the Java object Date -> what you already have as the result of  TalendDate.getCurrentDate() !!!
In the database a date is also stored in an internal binary format WITHOUT pattern of course!

I strongly suggest you invest some time and learn Java an some basic skills about databases like Oracle. It will make your life as developer much easier!