What is scheduled Apex?

What is Scheduled Apex?

When you want to run a piece apex code at some particular time within a period of time.Schedule apex is class which runs at a regular interval of time. To schedule an apex class we need to implement an interface Schedulable. If you want to run a piece to schedule code at the first of every month or day wise  you can use to make your life easier when you have to redeploy/change this code Scheduler apex runs as system mode that means whether the user has permission to execute the class or not, they can execute  the class.

Read: How to Update, Insert, Export or Delete Data Using Apex Data Loader?

public class queueableexmaple implements queueable {
}
To monitor the execution of a scheduled Apex job 
Navigation 
Setup =>Monitoring=>jobs=>Scheduled Jobs
Schedule class contains one method
globalvoid execute(SchedulableContext sc){
//your login 
}

The following are the values for the expression:

Name	Values	Special Characters
Seconds	0–59	None
Minutes	0–59	None
Hours	0–23	None
Day_of_month	1–31	, - * ? / L W
Month	1–12 or the following: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec	, - * /
Day_of_week	1–7 or the following: Sun, Mon, Tue, Wed, Thu, Fri, Sat	, - * ? / L #
optional year	null or 1970–2099	, - * /

The following are some examples of how to use the expression.

Expression	Description
0 0 0 ? * * *	at 12:00 AM every day
0 0 10 ? * *	at 10.00 AM every day
0 0 10 * * ?	at 10.00 AM every day
0 0 10 * * ? *	at 10.00 AM every day
0 0 15 ? * * *	at 3:00 PM every day
0 0-5 15 * * ?	Every minute starting at 3:00 PM and ending at 3:05 PM, every day
0 15 17 ? * MON-FRI	at 5:15 PM every Monday, Tuesday, Wednesday, Thursday and Friday
0 15 10 15 * ?	at 5:15 PM on the 15th day of every month
0 15 17 ? * 6#3	at 5:15 PM on the third Friday of every month
0 0 18 ? * 6L	runs the last Friday of every month at 6:00 PM.
‘0 30 * * * *’;	every 30 minutes
0 0 12 * * ?	at 12:00 PM every day
0 0 23 * * ? 2016	runs every day at 11:00 PM during the year 2016.
?	No value
*	All Value
L	Last

Example

Read: Wrapper Class Salesforce Tutorial Guide for Beginner

global class scheduledMonthly implements Schedulable {
          global void execute(SchedulableContext sc) {
             List<account> objectList = new List<account>();
             account a = new account();
              a.Name='Joshon & Joshon ';
              a.phone='+17-31441';
              a.Industry='Energy';
               account acc = new account();
              acc .Name='Brigstone';
              acc .phone='+12-3327325';
              acc .Industry='Goverment';
             objectList.add(a);
             objectList.add(acc);
            if (!objectList.isEmpty()) {
                insert objectList;
            }
    }
}

Job Scheduled

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