Calendar Date Calculation

Question

What's wrong with my following statement?
I always get compilation,
class XX
Calendar calendar = Calendar.getInstance();
Calendar cal1 = calendar.add(calendar.MONTH,1); //incompatible types error
Date expiry = cal1.getTime();
but I got the requirements asking for <identifier> in the 2nd version
class XX...
GregorianCalendar calendar = new GregorianCalendar();
calendar.add(calendar.MONTH, +1); //identifier need
Date expiry = calendar.getTime();
but it works when it is declared under
class {
public static void main(String[] args)
{  GregorianCalendar calendar = new GregorianCalendar();
calendar.add(calendar.MONTH, +1); //identifier need
Date expiry = calendar.getTime();
However, I am not going to declare it under main.
Pls help!

Answer 1

In the first two cases, you haven't put the statements in a method, where they belong. In the last, you did, so it worked. You can have methods other than main(), of course.
You should post real code and real error messages when you ask a question...