java code for creating a new worksheet in microsoft excel when the current worksheet exceeds the capacity

I am working on a product in java whereby a xml is parsed and converted to a microsoft excell sheet.The data is parsing properly  in the code where I am working .The data parsed is converted into an internal format and from that the data is converted to excel sheet.

I need java code to implement the functionality such that a new worksheet should be created in excel when the capacity of the current excel is exceeded