How to get prefix by the SOAP API

Hi,

i am using to call salesforce service using SOAP API in java plateform

i am created two custom object

but when i am using my app..it is asking about the prefix...

actually a have added prefix.. if i modify all the custom object and field with prefix then after making the package it calling the the object by according to the customer prefix...as prefix is depend upon the customer what he have created

can you help how to get the prefix of a ccount in java language using SOAP API SO the i will used the concat dynamically the prefix with custom object and field

Quick reply will be appreciated

Thanks

Raveendra