Anupama
You can use them as either binary or unary. Binary is the traditional x+y and x-y usage.
As unary the + re-enforces the fact that the variable/literal is a postive number, it will also promote the operand to an int if it is a byte, short or char..
The - makes an operand negative in value and will also promote to an int if it is a byte short or char.
for a more detailed explaination go here:
http://java.sun.com/docs/books/jls/second_edition/html/expressions.doc.html#24924 hope that answers your question.
Dave
[This message has been edited by Dave Vick (edited May 31, 2001).]