Here you can find the source of getDiffMon(Date dt, int idiff)
public static final String getDiffMon(Date dt, int idiff)
//package com.java2s; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.*; public class Main { public static final String dateFormat = "yyyy-MM-dd"; public static final String getDiffMon(Date dt, int idiff) { Calendar c = Calendar.getInstance(); c.setTime(dt);// w w w . ja v a 2 s.c om c.add(Calendar.MONTH, idiff); return dateFormat(c.getTime()); } public static final String dateFormat(Date date) { if (date == null) { return ""; } return getFormat(dateFormat).format(date); } public static final String format(Date date, String formate) { if (date == null) { return ""; } return getFormat(formate).format(date); } public static final String format(Long dateTmie, String formate) { Date date = new Date(dateTmie); return getFormat(formate).format(date); } public static final DateFormat getFormat(String format) { return new SimpleDateFormat(format); } }