1) getting earlier date from current date, 2) converting a yyyyMMdd to yyyMM format, 3) date comparision

java joda time operations

import org.joda.time.DateTime;
import org.joda.time.LocalDate;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;

import java.io.IOException;
import java.util.Calendar;
import java.util.Date;

DateTimeFormatter formatter = DateTimeFormat.forPattern( "yyyyMM");
        Calendar calendar = Calendar.getInstance();

        // get the current date
        // String currentDate = formatter.print(new DateTime(calendar.getTime()));

        calendar.add(Calendar.YEAR, -year); // subtract n year from the current date
        Date earlierDate = calendar.getTime(); // get the date
        String baseLineDateString = formatter.print(new DateTime(earlierDate)); // format the date to yyyyMM formatted string
        LocalDate baseLineDate = formatter.parseLocalDate(baseLineDateString); // convert the string to the LocalDate

        ////////////////////// this is for testing purpose /////////////////////////////////////
        DateTimeFormatter testDashedFormatter = DateTimeFormat.forPattern( "yyyy-MM-dd");
        String testBaseLineDate = "2016-05-23";
        DateTime testBaseLineDateTime = testDashedFormatter.parseDateTime(testBaseLineDate);
        String testBaseLineDateString = formatter.print(testBaseLineDateTime);
        LocalDate testLocalBaseLineDate = formatter.parseLocalDate(testBaseLineDateString);
        System.out.println("test baseline date: " + testLocalBaseLineDate);
        ///////////////////////////////////////////////////////////////////////////////////////

        DateTimeFormatter parserLongFormat = DateTimeFormat.forPattern("yyyy-MM-dd");
        String reportingDateLong = "2018-09-12";
        DateTime dateTime = parserLongFormat.parseDateTime(reportingDateLong);
        String reportingDateString = formatter.print(dateTime); // get the yyyyMM string formatted date
        LocalDate reportingDate = formatter.parseLocalDate(reportingDateString); // convert the string to the LocalDate

        System.out.println("reporting date: " + reportingDate);

        // boolean isBefore = reportingDate.isBefore(baseLineDate);
        boolean isBefore = reportingDate.isBefore(testLocalBaseLineDate);

        // System.out.println(reportingDate + " is before " + baseLineDate + " : " + isBefore);
        System.out.println(reportingDate + " is before " + testLocalBaseLineDate + " : " + isBefore);