Recipe Name:
Convert LocalDateTime getTimeInMillis to Instant toEpochMilli
Description:
Convert LocalDateTime getTimeInMillis to Instant toEpochMilli
Level:
warning
Language:
- java
Tags:
- java.time
- java.util.Calendar
- quality
Documentation
Migrate from java.util.Date and java.util.Calendar to Java Time
Prior to the Java SE 8 release, the Java date and time mechanism was provided by the java.util.Date, java.util.Calendar, and java.util.TimeZone classes, as well as their subclasses, such as java.util.GregorianCalendar.
These classes had several drawbacks, including:
- The Calendar class was not type safe.
- Because the classes were mutable, they could not be used in multithreaded applications.
- Bugs in application code were common due to the unusual numbering of months and the lack of type safety.
Perhaps you have legacy code that uses the java.util date and time classes and you would like to take advantage of the java.time functionality with minimal changes to your code.
Examples
Before
Calendar calendar = new GregorianCalendar(2020, 05, 10, 10, 30);
calendar.add(Calendar.YEAR, 1);
After
LocalDateTime calendar = LocalDateTime.of(2020, 05, 10, 10, 30);
calendar.plusYears(1);
References
Recipe
id: scw:calendar:get-time-in-millis-localdatetime
version: 10
metadata:
name: Convert LocalDateTime getTimeInMillis to Instant toEpochMilli
shortDescription: Convert LocalDateTime getTimeInMillis to Instant toEpochMilli
level: warning
language: java
enabled: true
comment: 'Be aware this recipe uses a system default timezone (ZoneId.systemDefault()). '
descriptionFile: Java/Date-Calendar/descriptions/date-calendar.html
tags: java.time;java.util.Calendar;quality
search:
methodcall:
name: getTimeInMillis
type: java.time.LocalDateTime
availableFixes:
- name: Rewrite using toInstant().toEpochMilli()
actions:
- rewrite:
to: '{{{ qualifier }}}.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli()'