Options setting of java concurrent program

Hi Experts

Regarding the following question,if you have any idea,could you please share with me?

Regarding java concurrent program

eg:Format Payment Instructions with Text Output

1.On Concurrent Programs form,

if we set Options as following

set Options

-Xmx1024m -Xss4096k

-Xmx (-mx): maximum heap size

-Xss : Java stack size

Then when we run this concurrent program, even the data is not too much, will 1024MB memory be allocated for this concurrent program?

Or will the proper memory that (larger than 384MB and less than 1024MB) according the amount of data be allocated?

2.when we don’t set option,then it will use 384m as default per AFJSMARG