To get Start and End date by given Month, Year and Day

import java.util.Calendar;
import java.util.Date;

public class HelloWorld {

	public static void main(String[] args) {

		Date fromDate = getFromDate(2014, 7, null);
		System.out.println(" From Date is  " + fromDate);

		fromDate = getFromDate(2014, 7, 14);
		System.out.println(" From Date is  " + fromDate);

		Date toDate = getToDate(2014, 7, null);
		System.out.println(" To Date is  " + toDate);

		toDate = getToDate(2014, 7, 14);
		System.out.println(" To Date is  " + toDate);

	}

	private static Date getFromDate(Integer year, Integer month, Integer day) {
		// Setup a Calendar instance.
		Calendar cal = Calendar.getInstance();
		cal.setLenient(false);
		// Set the year as 2009
		cal.set(Calendar.YEAR, year);
		// Set the month as February (can be set as 1 or Calendar.FEBRUARY)
		cal.set(Calendar.MONTH, month);
		// Set the date as 1st - optional
		if (day == null)
			cal.set(Calendar.DATE, 1);
		else
			cal.set(Calendar.DAY_OF_MONTH, day);
		cal.set(Calendar.HOUR_OF_DAY, 0);
		cal.set(Calendar.MINUTE, 0);
		cal.set(Calendar.SECOND, 0);
		return cal.getTime();
	}

	private static Date getToDate(Integer year, Integer month, Integer day) {
		// Setup a Calendar instance.
		Calendar cal = Calendar.getInstance();
		cal.setLenient(false);
		// Set the year as 2009
		cal.set(Calendar.YEAR, year);
		// Set the month as February (can be set as 1 or Calendar.FEBRUARY)
		cal.set(Calendar.MONTH, month - 1);
		// Set the date as 1st - optional

		if (day == null) {
			int lastDateOfMonth = cal.getActualMaximum(Calendar.DATE);
			cal.set(Calendar.DATE, lastDateOfMonth);
		} else
			cal.set(Calendar.DAY_OF_MONTH, day);
		cal.set(Calendar.HOUR_OF_DAY, 23);
		cal.set(Calendar.MINUTE, 59);
		cal.set(Calendar.SECOND, 59);
		return cal.getTime();
	}
}

Output:

From Date is  Fri Aug 01 00:00:00 IST 2014
From Date is  Thu Aug 14 00:00:00 IST 2014
To Date is  Thu Jul 31 23:59:59 IST 2014
To Date is  Mon Jul 14 23:59:59 IST 2014