windows user access check

i want to execute commands, but while executing commands authenticate users via the windows username,password with thier rights to execute the command...pls help me
[171 byte] By [proj@BEa] at [2007-11-26 13:48:16]
# 1
itz quite urgent ....can any1 gimme an idea as to how i should go about it...pls...itz a request
proj@BEa at 2007-7-8 1:24:15 > top of Java-index,Security,Other Security APIs, Tools, and Issues...