get the last day in a month in java

from http://forum.java.sun.com/thread.jspa?threadID=700253&messageID=4063642
it says:

// create calendar instance :: now
Calendar calendar = Calendar.getInstance();
int lastDateofThisMonth = calendar.getActualMaximum(Calendar.DATE);



Just check this one and understand how to expand

// create calendar instance :: now
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.YEAR,2000);
// month 0 is january
calendar.set(Calendar.MONTH,1);
int lastDateofMonth = calendar.getActualMaximum(Calendar.DATE);
System.out.println(lastDateofMonth);