A JodaTime and java.util.Date Util Class with a lot of usefull functions.

DateTimeUtil.java

package cm.flashbusiness.core.util;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.joda.time.DateTime;

/**
 * @author dassi
 */
public class DateTimeUtil {
	
	public static final String FOMAT_ONE = "dd/MM/yyyy HH:mm";

	public static final Integer CURRENT_YEAR = DateTime.now().getYear();
	public static final Integer CURRENT_MONTH = DateTime.now().getMonthOfYear();
	public static final Integer CURRENT_DAY = DateTime.now().getDayOfMonth();

	public static final Integer LAST_MONTH_OF_CURRENT_YEAR = DateTime.now()
			.monthOfYear().getMaximumValue();
	public static final Integer FIRST_MONTH_OF_CURRENT_YEAR = DateTime.now()
			.monthOfYear().getMinimumValue();

	public static final Integer LAST_DAY_OF_CURRENT_MONTH = DateTime.now()
			.dayOfMonth().getMaximumValue();
	public static final Integer FIRST_DAY_OF_CURRENT_MONTH = DateTime.now()
			.dayOfMonth().getMinimumValue();

	public static final Integer LAST_HOUR_OF_CURRENT_DAY = DateTime.now()
			.hourOfDay().getMaximumValue();
	public static final Integer FIRST_HOUR_OF_CURRENT_DAY = DateTime.now()
			.hourOfDay().getMinimumValue();

	public static final Integer LAST_MINUTE_OF_CURRENT_HOUR = DateTime.now()
			.minuteOfHour().getMaximumValue();
	public static final Integer FIRST_MINUTE_OF_CURRENT_HOUR = DateTime.now()
			.minuteOfHour().getMinimumValue();

	public static final Integer LAST_SECOND_OF_CURRENT_MINUTE = DateTime.now()
			.secondOfMinute().getMaximumValue();
	public static final Integer FIRST_SECOND_OF_CURRENT_MINUTE = DateTime.now()
			.secondOfMinute().getMinimumValue();

	public static DateTime getFirstDateOfDay() {
		return new DateTime(CURRENT_YEAR, CURRENT_MONTH, CURRENT_DAY,
				FIRST_HOUR_OF_CURRENT_DAY, FIRST_MINUTE_OF_CURRENT_HOUR,
				FIRST_SECOND_OF_CURRENT_MINUTE);
	}

	public static DateTime getLastDateOfDay() {
		return new DateTime(CURRENT_YEAR, CURRENT_MONTH, CURRENT_DAY,
				LAST_HOUR_OF_CURRENT_DAY, LAST_MINUTE_OF_CURRENT_HOUR,
				LAST_SECOND_OF_CURRENT_MINUTE);
	}

	public static DateTime getFirstDateOfMonth() {
		return new DateTime(CURRENT_YEAR, CURRENT_MONTH,
				FIRST_DAY_OF_CURRENT_MONTH, FIRST_HOUR_OF_CURRENT_DAY,
				FIRST_MINUTE_OF_CURRENT_HOUR, FIRST_SECOND_OF_CURRENT_MINUTE);
	}

	public static DateTime getLastDateOfMonth() {
		return new DateTime(CURRENT_YEAR, CURRENT_MONTH,
				LAST_DAY_OF_CURRENT_MONTH, LAST_HOUR_OF_CURRENT_DAY,
				LAST_MINUTE_OF_CURRENT_HOUR, LAST_SECOND_OF_CURRENT_MINUTE);
	}

	public static DateTime getFirstDateOfYear() {
		return new DateTime(CURRENT_YEAR, FIRST_MONTH_OF_CURRENT_YEAR,
				FIRST_DAY_OF_CURRENT_MONTH, FIRST_HOUR_OF_CURRENT_DAY,
				FIRST_MINUTE_OF_CURRENT_HOUR, FIRST_SECOND_OF_CURRENT_MINUTE);
	}

	public static DateTime getLastDateOfYear() {
		return new DateTime(CURRENT_YEAR, LAST_MONTH_OF_CURRENT_YEAR,
				LAST_DAY_OF_CURRENT_MONTH, LAST_HOUR_OF_CURRENT_DAY,
				LAST_MINUTE_OF_CURRENT_HOUR, LAST_SECOND_OF_CURRENT_MINUTE);
	}

	public static DateTime getLastDateOfDate(DateTime dateTime) {
		return new DateTime(dateTime.getYear(), dateTime.getMonthOfYear(),
				dateTime.getDayOfMonth(), dateTime.hourOfDay()
						.getMaximumValue(), dateTime.minuteOfHour()
						.getMaximumValue(), dateTime.secondOfMinute()
						.getMaximumValue());
	}

	public static DateTime getFirstDateOfDate(DateTime dateTime) {
		return new DateTime(dateTime.getYear(), dateTime.getMonthOfYear(),
				dateTime.getDayOfMonth(), dateTime.hourOfDay()
						.getMinimumValue(), dateTime.minuteOfHour()
						.getMinimumValue(), dateTime.secondOfMinute()
						.getMinimumValue());
	}

	public static DateTime getFirstDateOfMonth(DateTime dateTime) {
		return new DateTime(dateTime.getYear(), dateTime.getMonthOfYear(),
				dateTime.dayOfMonth().getMinimumValue(), dateTime.hourOfDay()
						.getMinimumValue(), dateTime.minuteOfHour()
						.getMinimumValue(), dateTime.secondOfMinute()
						.getMinimumValue());
	}

	public static DateTime getLastDateOfMonth(DateTime dateTime) {
		return new DateTime(dateTime.getYear(), dateTime.getMonthOfYear(),
				dateTime.dayOfMonth().getMaximumValue(), dateTime.hourOfDay()
						.getMaximumValue(), dateTime.minuteOfHour()
						.getMaximumValue(), dateTime.secondOfMinute()
						.getMaximumValue());
	}

	public static DateTime getLastDateOfYear(DateTime dateTime) {
		return new DateTime(dateTime.getYear(), dateTime.monthOfYear()
				.getMaximumValue(), dateTime.dayOfMonth().getMaximumValue(),
				dateTime.hourOfDay().getMaximumValue(), dateTime.minuteOfHour()
						.getMaximumValue(), dateTime.secondOfMinute()
						.getMaximumValue());
	}

	public static DateTime getFirstDateOfYear(DateTime dateTime) {
		return new DateTime(dateTime.getYear(), dateTime.monthOfYear()
				.getMinimumValue(), dateTime.dayOfMonth().getMinimumValue(),
				dateTime.hourOfDay().getMinimumValue(), dateTime.minuteOfHour()
						.getMinimumValue(), dateTime.secondOfMinute()
						.getMinimumValue());
	}
	
	public static String converterToString(Date date, String format){
		if(date == null){
			return "";
		}
		SimpleDateFormat formater = new SimpleDateFormat(format);
		return formater.format(date);
		
	}
	
	public static Date converterToDate(String stringDate) throws ParseException{
		SimpleDateFormat formater = new SimpleDateFormat(FOMAT_ONE);
		return formater.parse(stringDate);
		
	}

}

Very usefull.thanks