Spring cron vs normal cron?

java

cron-expressions

spring-cron

unix-cron

byNikita Barsukov·Mar 7, 2025

Spring cron is a feature of the Spring framework. It enables precise scheduling of tasks within your Java applications down to the second. The defining of tasks is as easy as using the @Scheduled annotation.

Spring cron: 0 0 9 * * ? (runs at 9 AM daily) UNIX cron: 0 9 * * * (runs at 9 AM daily)

The configuration of a task in Spring is as follows:

@Scheduled(cron = "0 0 9 * * ?") // This task needs coffee ☕
public void dailyTask() {
    // Task logic here
}

While Spring cron offers Application context awareness and springs up to the expectations of Java developers, UNIX cron schedules tasks at the system level.

Spring and Unix cron: The fields of dreams (and nightmares)

Every Spring cron pattern follows a 6-field format, and every Unix cron abides by a 5-field format. Knowing their differences is crucial.

Spring cron example: 0 15 10 * * 1-5 - translates to 10:15AM, Monday to Friday.

UNIX cron example: 15 10 * * 1-5 - same schedule, but doesn't care about seconds.

Remember: Always follow the zero policy in the seconds field for Spring patterns, and Spring despises the 7th 'year' field. That's so last year! 💁‍♀️

Don't brass your cron expressions

When crafting Spring cron expressions, you can use day aliases such as "MON-FRI" for clarity. For instance, "0 0 18 * * 1-5" becomes "0 0 18 * * MON-FRI".

Words of caution for spring cron expressions:

Spring cron isn't a fan of the 7th 'year' field. Use it and prepare for a boot time exception.
Turn to Spring-specific documentation, such as CronSequenceGenerator for getting your Spring cron right. Dry documentation, but it gets the job done.
Be wary of online cron tools. They may give you incorrect advice for Spring cron.

Deploying crons in the wild

Now that we know the differences, let's see some practical applications.

Hourly tasks

Spring cron: "0 0 */1 * * *" - This one ticks every hour, on the hour.
UNIX cron: "0 */1 * * *" - Close, but not as precise.

First Sunday of the month

Spring cron: "0 0 0 ? * SUN#1" - This bird chirps at midnight every first Sunday.
UNIX cron: Well, UNIX cron is sleeping on Sundays.

Every 8 hours

Spring cron: "0 0 */8 * * *" - This one goes off like clockwork: 12 AM, 8 AM, and 4 PM.
UNIX cron: "0 */8 * * *" - Good try, but no second precision.

In each scenario, Spring cron proves to be more flexible accommodating for more complex scheduling needs.