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.

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

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