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New date time API is introduced in Java 8 to overcome the following drawbacks of old date-time API :

• Not thread safe : Unlike old java.util.Date which is not thread safe the new date-time API is immutable and doesn't have setter methods.
• Less operations : In old API there are only few date operations but the new API provides us with many date operations.

Java 8 under the package java.time introduced a new date-time API, most important classes among them are

• Local : Simplified date-time API with no complexity of timezone handling.
• Zoned : Specialized date-time API to deal with various timezones.
• LocalDate/LocalTime: These classes are used to represent date and time respectively, where timezones are not required.
• ZonedDateTime: Used when the time zone needs to be taken into account alongside the date and time.
• ChronoUnit Enum: The ChronoUnit enum, added in the new Java 8 API, is used to represent units like day, month, etc., and is available in the java.time.temporal package.

public class NewDateTimeApiExamples {

    public static void main(String args[]) {

        // current date and time
        LocalDateTime currentTime = LocalDateTime.now();
        System.out.println("Current DateTime: " + currentTime);

        LocalDate date1 = currentTime.toLocalDate();
        System.out.println("date1: " + date1);

        Month month = currentTime.getMonth();
        int day = currentTime.getDayOfMonth();
        int seconds = currentTime.getSecond();

        System.out.println("Month: " + month + " day: " + day + " seconds: " + seconds);

        // current date and time
        ZonedDateTime date = ZonedDateTime.parse("2019-07-28T10:14:20+05:30[Asia/Kolkata]");
        System.out.println("date: " + date);

        // Get the current date
        LocalDate currentDate = LocalDate.now();
        System.out.println("Current date: " + currentDate);

        // add 1 week to the current date
        LocalDate nextWeek = currentDate.plus(1, ChronoUnit.WEEKS);
        System.out.println("Next week: " + nextWeek);

        // add 2 month to the current date
        LocalDate nextMonth = currentDate.plus(2, ChronoUnit.MONTHS);
        System.out.println("Next month: " + nextMonth);

        // add 3 year to the current date
        LocalDate nextYear = currentDate.plus(3, ChronoUnit.YEARS);
        System.out.println("Next year: " + nextYear);

        // add 10 years to the current date
        LocalDate nextDecade = currentDate.plus(1, ChronoUnit.DECADES);
        System.out.println("Next ten year: " + nextDecade);

        // comparing dates
        LocalDate date2 = LocalDate.of(2014, 1, 15);
        LocalDate date3 = LocalDate.of(2019, 7, 28);

        if (date2.isAfter(date3)) {
        System.out.println("date2 comes after date3");
        } else {
        System.out.println("date2 comes before date3");
        }

        // check Leap year
        if (date1.isLeapYear()) {
        System.out.println("This year is Leap year");
        } else {
        System.out.println(date1.getYear() + " is not a Leap year");
        }

        //How many days, month between two dates
        LocalDate newDate = LocalDate.of(2019, Month.DECEMBER, 14);
        Period periodTonewDate = Period.between(date1, newDate);
        // Note: getMonths() returns only the "months" component of the Period (0-11),
        // not the total number of months between the dates. It matches here because
        // the gap is under a year; for a true total use ChronoUnit.MONTHS.between(date1, newDate).
        System.out.println("Months left between today and newDate : " + periodTonewDate.getMonths() );

    }

}

Output

Current DateTime: 2019-07-28T02:26:31.367
date1: 2019-07-28
Month: JULY
day: 28
seconds: 31
date: 2019-07-28T10:14:20+05:30[Asia/Kolkata]
Current date: 2019-07-28
Next week: 2019-08-04
Next month: 2019-09-28
Next year: 2022-07-28
Next ten year: 2029-07-28
date2 comes before date3
2019 is not a Leap year
Months left between today and newDate : 4