I sometimes ask this as an interview question, and the only good answer is
to ask me questions about what exactly I want.  I'll do the same: please
specify what you mean by "number of months between two dates".

How many months are between Jan 1 and Jan 2?  Jan 1 and Jan 30?  Jan 1 2007
and Dec 31 2006?  Feb 1 and 28 days afterward in 2007?  in 2008?

For most reasonable definitions, the java.util.Calendar class will get you the
information you need to calculate the answer.
--
Mark Rafn    dagon@dagon.net    <http://www.dagon.net/>

      Calendar calendar1 = new GregorianCalendar();
      Date trialTime = new Date();
      calendar1.setTime(trialTime);
      int month1 = calendar1.get(Calendar.MONTH);
      Date monthAhead = new Date();
      Calendar calendar2 = new GregorianCalendar();
      calendar2.setTime(monthAhead);
      calendar2.roll(Calendar.MONTH, 8);
      int month2 = calendar2.get(Calendar.MONTH);
      System.out.println("Month 1  = " + month1 );
      System.out.println("Month 2  = " + month2 );

Month 1  = 2
Month 2  = 10

Once you have the months from both dates, you can manipulate them.

Dinesh