Apex Scheduler Class

First apex scheduler class:

global class Scheduler01 implements Schedulable {

    global void execute(SchedulableContext SC)    

    {

        //Call other class method which will perform operations as it is

        //recommended that all processing take place in a separate class

        doScheduling();

    }

    public void doScheduling(){

       try{

            dateTime dt=System.now().addMinutes(10); //you can specify 10 mins or 15    

                                                                              //mins or any interval

            String Csec,Cmin,Chr,Cday,Cmonth,CYear;

            Csec=String.valueof(dt.second());

            Cmin=String.valueof(dt.minute());

            Chr=String.valueof(dt.hour());

            Cday=String.valueof(dt.day());

            Cmonth=String.valueof(dt.month());

            CYear=String.valueof(dt.Year());

            String SchTimer=Csec+' '+Cmin+' '+Chr+' '+Cday+' '+Cmonth+' ? '+CYear;

            system.debug('*************SchTimer:'+SchTimer);

            Scheduler02 cas = new Scheduler02();

            system.schedule('Scheduler02: Running at '+System.now().format(), SchTimer, cas);

            //we will delete completed apex scheduled jobs for which state is DELETED

            for( CronTrigger c:[Select State,Id,EndTime,CronExpression From CronTrigger where 

                                        NextFireTime= null  AND State='DELETED' Limit 100]){

                    System.abortJob(c.id);

            }

        }

        catch(exception e){

        }

   }

}

Second apex Scheduler Class:

global class Scheduler02 implements Schedulable {

    global void execute(SchedulableContext SC){

        //Call other class method which will perform operations as it is

        //recommended that all processing take place in a separate class

        doScheduling();

    }

    public void doScheduling(){

      try{

            dateTime dt=System.now().addMinutes(10);

            String Csec,Cmin,Chr,Cday,Cmonth,CYear;

            Csec=String.valueof(dt.second());

            Cmin=String.valueof(dt.minute());

            Chr=String.valueof(dt.hour());

            Cday=String.valueof(dt.day());

            Cmonth=String.valueof(dt.month());

            CYear=String.valueof(dt.Year());

            String SchTimer=Csec+' '+Cmin+' '+Chr+' '+Cday+' '+Cmonth+' ? '+CYear;

            system.debug('*************SchTimer:'+SchTimer);

            Scheduler01 cas = new Scheduler01();

            system.schedule('Scheduler01: Running at '+System.now().format(), SchTimer, cas);

            //we will delete completed apex scheduled jobs for which state is DELETED

            for( CronTrigger c:[Select State,Id,EndTime,CronExpression From CronTrigger 

                                where NextFireTime=null  AND State='DELETED' Limit 100]){

                    System.abortJob(c.id);

            }

        }

        catch(exception e){

        }

    }

}