Use ThreadPoolTaskScheduler without using Spring framework

I am trying to use ThreadPoolTaskScheduler to schedule task using CRON but without using Spring framework. I created 2 task scheduler for daily and weekly.

So, far here is what i tried:

public class MyClass {

        public static void main(String args[]) {
           MyClass mc = new MyClass();
           mc.runTaskScheduler();
        }

        private void runTaskScheduler() {
            Runnable dailyScheduler = this::processDaily;
            Runnable weeklyScheduler = this::processWeekly;

            ThreadPoolTaskScheduler threadPoolTaskScheduler = new ThreadPoolTaskScheduler();
            threadPoolTaskScheduler.initialize();
            threadPoolTaskScheduler.schedule(dailyScheduler, new CronTrigger("0 * * * * *")); //0 * * * * *
        threadPoolTaskScheduler.schedule(weeklyScheduler, new CronTrigger("0 1 * * * *")); //0 1 * * * *
        
        }

        private void processDaily() {
           // some code
        }

        private void processWeekly() {
          // some code
        }

    }

I am not sure if should i need to make ThreadPoolTaskScheduler threadPoolTaskScheduler = new ThreadPoolTaskScheduler(); static variable?

I tried to make a main class but not sure if I did it correct.

There are couple of things to mention...

First of all, if you use the Spring Scheduling library you are using the Spring framework. Spring is intended to make your live easier, therefore it uses a lot of preconfigured stuff, in case you do not provide any particular configuration.
If you do not want to use Spring and still need a cron like scheduling, take a look at the Quartz Job Scheduler.

Second, your Cron job is not daily and weekly, but minutely and hourly.
According to the docu, daily is 0 0 0 * * * and weekly 0 0 0 * * 0

Finally, your code works. There is no need to flag the ThreadPoolTaskScheduler as static. Of course you could turn your ThreadPoolTaskScheduler into a Singleton, if you want to use just a single instance of it. But be aware, that in the opinion of many, Singletons are a code smell.

import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import org.springframework.scheduling.support.CronTrigger;

import java.util.Date;
    
public class MyClass {

    private static ThreadPoolTaskScheduler THREAD_POOL_TASK_SCHEDULER;

    public static ThreadPoolTaskScheduler getInstance () {
        if (THREAD_POOL_TASK_SCHEDULER == null) {
            THREAD_POOL_TASK_SCHEDULER = new ThreadPoolTaskScheduler();
            THREAD_POOL_TASK_SCHEDULER.initialize();
        }
        return THREAD_POOL_TASK_SCHEDULER;
    }

    public static void main(String args[]) {
        MyClass mc = new MyClass();
        mc.runTaskScheduler();
    }

    private void runTaskScheduler() {
        Runnable minutelyScheduler = this::processMinutely;
        getInstance().schedule(minutelyScheduler, new CronTrigger("0 * * * * *")); //0 1 * * * *
    }

    private void processMinutely() {
        System.out.println("Time " + new Date());
    }

}

Or you could just use the scheduler as a class variable...

import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import org.springframework.scheduling.support.CronTrigger;

import java.util.Date;

public class MyClass {

    public static void main(String args[]) {
        MyClass mc = new MyClass();
        mc.runTaskScheduler();
    }

    private final ThreadPoolTaskScheduler threadPoolTaskScheduler;

    public MyClass() {
        threadPoolTaskScheduler = new ThreadPoolTaskScheduler();
        threadPoolTaskScheduler.initialize();
    }

    private void runTaskScheduler() {
        Runnable minutelyScheduler = this::processMinutely;
        threadPoolTaskScheduler.schedule(minutelyScheduler, new CronTrigger("0 * * * * *")); //0 1 * * * *
    }

    private void processMinutely() {
        System.out.println("Time " + new Date());
    }

}

Both examples make sense, in case you want to avoid multiple instances of the scheduler or if you want to access it later on.

If you work with just Java and not Spring/SpringBoot your options are to use some 3d party library such as Quartz Job Scheduler or use Java provided classes for that. Here are the classes you might want to use:
ScheduledExecutorService interface and its implementation: ScheduledThreadPoolExecutor. Also look at class Executors and its method public static ScheduledExecutorService newSingleThreadScheduledExecutor(). <br><br>
Also, as far as 3d parties go I wrote my own scheduler. Look at Javadoc. This Background runner comes as part of Open Source MgntUtils library written and maintained by me. Also the source code of the library contains working example on how to use the Background Runner. The library including the source code can be downloaded from Github here and an example can be seen here. Also, the library can be obtained as Maven artifacts from Maven central here