code: public String getEasterSunday(int year, int days) {
  		int K = year / 100;
  		int M = 15 + ( ( 3 * K + 3 ) / 4 ) - ( ( 8 * K + 13 ) / 25 );
  		int S = 2 - ( (3 * K + 3) / 4 );
  		int A = year % 19;
  		int D = ( 19 * A + M ) % 30;
  		int R = ( D / 29) + ( ( D / 28 ) - ( D / 29 ) * ( A / 11 ) );
  		int OG = 21 + D - R;
  		int SZ = 7 - ( year + ( year / 4 ) + S ) % 7;
  		int OE = 7 - ( OG - SZ ) % 7;
  		int OS = OG + OE;
  		
  		SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
  		Calendar c = Calendar.getInstance();
  		String date;
  		
  		if( OS <= 31 ) {
  			date = String.format("%04d-03-%02d", year, OS);
  		}
  		else{
  			date = String.format("%04d-04-%02d", year, ( OS - 31 ) );
  		}		
  		try{
  			c.setTime(formatter.parse(date));
  			c.add(Calendar.DAY_OF_MONTH, days);
  			date = formatter.format(c.getTime());
  		} catch (ParseException e) {
  			e.printStackTrace();
  		}
  		return date;
  	}
docs: Get the date of a day relative to Easter Sunday in a given year. Algorithm used is from the "Physikalisch-Technische Bundesanstalt Braunschweig" PTB.
  
  @author Hans-Peter Pfeiffer
  @param year
  @param days
  @return date