New to Java

i am a newbie to java and require ur urgent help plzzzz.
i wanna perform binary addition,subtraction and modulus operation between two numbers of 512 bit without using java functions i.e by simple logics of control statements.i need to convert two 512 bit numbers passed as string into binary form, and then perform addition,subtraction and modulus operations on these two binary numbers and finally dipaly the result in decimal format.
i think we may use full adder binary logic in this!!!

please send me the java coding for these three operations as urgent as possible on my email.
i would be highly obliged.

thanks.

sheetal.