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How to create/ update task to run in future using Timer in microservice system

[Problem]
I have service that have multiple instance and run in microservice system.
In service, I use Timer instance to run task in future
public class CustomizedTimerTask extends TimerTask {
private String message;
private String sender;
private String reciver;
#Override
public void run() {
// todo somthing
}
}
#Service
public MyTimerService {
public void initAfterStartOn() {
// get all task that have due date greater than now
// for_each and call newTask() function
}
public void newTask() {
Date startedAt = new Date(new Date().getTime() + ((long)5 * 60 * 60);
CustomizedTimerTask timerTask = new CustomizedTimerTask();
timerTask.setSender("sender");
timerTask.setRevicer("receiver");
timerTask.setMessage("Hi, nice to meet you");
timer.schedule(new CustomizedTimerTask(), new Date(startedAt));
// save CustomizedTimerTask to Database
}
}
Everything will be ok if I run only one instance. But if I have multiple instance and one of all is down and run later. It will run initAfterStartOn() it cause task will be duplicate.
Can someone give me advice on this?
Currently, I have not found any solution yet.

You can try using #Scheduled annotation
#Scheduled (cron = "0 0/10 * * * *", zone = "IST")
#SchedulerLock(name="createPromotionJob",lockAtLeastFor = "PTSM",lockAtMostFor="PTOM")
public void scheduledCreatePromotion() {

How to make Java code that opens the program hourly

I'm trying to make code that opens hourly programs made in Java. I have little knowledge of java. I tried to do similar below but it doesn't work as I want.
Code:
public static void main(String[] args) throws Exception {
for(int i = 0; i < 5; i++) {
Runtime runtime = Runtime.getRuntime();
String[] s = new String[] {"C:\\Program Files\\BraveSoftware\\Brave-Browser\\Application\\brave.exe"};
Process process = runtime.exec(s);
}
}

If you are looking for running this program in a scheduled manner, you can use something like
Task Scheduler in windows or Crontab in case of UNIX systems.
You need not install and run Java for that. But, if you really need it to be executed using a java code, then you can use inbuilt scheduling options in Java. One of the approach is to use a TimerTask . Added an example below
public class Task extends TimerTask {
#Override
public void run() {
try {
// I don't know, what is this app, basically you execute the logic here
Runtime runtime = Runtime.getRuntime();
String[] s = new String[] { "C:\\Program Files\\BraveSoftware\\Brave-Browser\\Application\\brave.exe" };
Process process = runtime.exec(s);
} catch (IOException e) {
// Do your thing with the errors!
e.printStackTrace();
}
}
}
And your scheduler goes like this.
public class Scheduler {
public static void main(String[] args) {
//Create a timer for scheduling
Timer schduleManager = new Timer();
//Create your task instance
Task taskInstance = new Task();
//Scheduler your task repeatedly - every one hour
schduleManager.schedule(taskInstance, 0, TimeUnit.HOURS.toMillis(1));
System.out.println(TimeUnit.HOURS.toMillis(1));
// Keep your code running - an eg.
while(true);
}
}
The program has to be exited forcefully with a Cntrl+C or console kill. There are other similar options , using different libraries as well, like
java.util.concurrent.ScheduledExecutorService
Quartz Scheduler
And more. You can explore on this.

If you are using spring boot then you can use Scheduler annotation
#Scheduled(fixedDelay = 60 * 60 * 1000

This seems to be a job requiring Java's ScheduledExecutorService. According to Java's documentation
The ScheduledExecutorService interface supplements the methods of its
parent ExecutorService with schedule, which executes a Runnable or
Callable task after a specified delay. In addition, the interface
defines scheduleAtFixedRate and scheduleWithFixedDelay, which executes
specified tasks repeatedly, at defined intervals.
Here's an example from its Javadoc that sets up a ScheduledExecutorService to beep every ten seconds for an hour:
import static java.util.concurrent.TimeUnit.*;
class BeeperControl {
private final ScheduledExecutorService scheduler =
Executors.newScheduledThreadPool(1);
public void beepForAnHour() {
final Runnable beeper = new Runnable() {
public void run() { System.out.println("beep"); }
};
final ScheduledFuture<?> beeperHandle =
scheduler.scheduleAtFixedRate(beeper, 10, 10, SECONDS);
scheduler.schedule(new Runnable() {
public void run() { beeperHandle.cancel(true); }
}, 60 * 60, SECONDS);
}
}
Here is a link to a StackOverflow answer that uses ScheduledExecutorService to run a task at a specific time.
Another alternative is to run your task as a CRON job. Here's a link to a StackOverflow answer that uses CRON to schedule a Java program.

If I understood your question correctly you can use Thread.sleep() to idle and then start the Process.
So I guess something like this would work:
public static void main(String[] args) throws InterruptedException, IOException {
ProcessBuilder pb = new ProcessBuilder("path\\to\\file.exe");
while (true) {
pb.start();
Thread.sleep(Duration.ofHours(1).toMillis());
}
}

Reset mysql colum values to default after specific using Servlet

I am new to web development I am making some web services using java servlets, and I am stuck in so many How to do it? stuff :(
I am developing an application in which I need to reset the mysql table column values back to default values at some time let's say we need to reset the counter # every Sunday 10:00 pm.
is there any thing like alarm manager in Java or mysql that can run all the time in background and trigger # specific time.
Thanks,

Java has a good interface ScheduledExecutorService.
You can try this code
ScheduledExecutorService service = Executors.newScheduledThreadPool(1);
//every day to execute
long everyDayDelay = 24*60*60*1000;
//first time to execute, it can be your special date
//for example 5 seconds after launch
long timeToExecute = System.currentTimeMillis()+5*1000;
service.scheduleWithFixedDelay(new Task(), getTimeToLaunch(timeToExecute), everyDayDelay, TimeUnit.MILLISECONDS);
where
//return difference between now and timeToExecute
public static long getTimeToLaunch(long timeToExecute){
long current = System.currentTimeMillis();
return timeToExecute - current;
}
class Task implements Runnable{
#Override
public void run() {
System.out.println("Run task!");
}
}
UPDATE: Class to execute your sql-tasks
public class SqlExecutionService1 {
public static final long everyDayDelay = 24*60*60*1000;
public SqlExecutionService1(){
ScheduledExecutorService service = Executors.newScheduledThreadPool(1);
//every day to execute
//first time to execute
//for example 5 seconds after launch
long timeToExecute = System.currentTimeMillis()+5*1000;
service.scheduleWithFixedDelay(new SqlTask1(), getTimeToLaunch(timeToExecute), everyDayDelay, TimeUnit.MILLISECONDS);
}
private long getTimeToLaunch(long timeToExecute){
long current = System.currentTimeMillis();
return timeToExecute - current;
}
}
class SqlTask1 implements Runnable{
#Override
public void run() {
//your sql tasks
}
}
To create this class, when your app server starts - use method init() in one of your main servlets.
Example -
public class MainInitServlet extends HttpServlet {
public void init() {
new SqlExecutionService1();
}
}

The Data of a Database should be the basis for calculation, not the result of calculations. In example Bills wont ever be successfully revised.
I guess this fact will ever be a clash between Programmers and Architects.

you might also use the event scheduling mechanism of mysql
this depends on the version of mysql and whether it is enabled or not

is there any thing like alarm manager in Java or mysql that can run all the time in background and trigger # specific time.
look at a API called Quartz , where your program can schedule Jobs and it will run it at that time.
use method execute(JobExecutionContext jobExecution) use to fire trigger.
EG:
SchedulerFactory schedulerFactory = new StdSchedulerFactory();
// Retrieve scheduler
Scheduler scheduler = null;
try {
scheduler = schedulerFactory.getScheduler();
}
catch (SchedulerException e) {
e.printStackTrace();
}
//this is a job
JobDetail job = new JobDetail("jobDetail", "jobDetailGroup", ImplementedJob.class);
SimpleTrigger trigger = new SimpleTrigger("Trigger Name","defaultGroup", DATE);
// schedule
scheduler.scheduleJob(job, trigger);
// start the scheduler
scheduler.start();

How to schedule a periodic task in Java?

I need to schedule a task to run in at fixed interval of time. How can I do this with support of long intervals (for example on each 8 hours)?
I'm currently using java.util.Timer.scheduleAtFixedRate. Does java.util.Timer.scheduleAtFixedRate support long time intervals?

Use a ScheduledExecutorService:
private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
scheduler.scheduleAtFixedRate(yourRunnable, 8, 8, TimeUnit.HOURS);

You should take a look to Quartz it's a java framework wich works with EE and SE editions and allows to define jobs to execute an specific time

Try this way ->
Firstly create a class TimeTask that runs your task, it looks like:
public class CustomTask extends TimerTask {
public CustomTask(){
//Constructor
}
public void run() {
try {
// Your task process
} catch (Exception ex) {
System.out.println("error running thread " + ex.getMessage());
}
}
}
Then in main class you instantiate the task and run it periodically started by a precised date:
public void runTask() {
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
calendar.set(Calendar.HOUR_OF_DAY, 15);
calendar.set(Calendar.MINUTE, 40);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
Timer time = new Timer(); // Instantiate Timer Object
// Start running the task on Monday at 15:40:00, period is set to 8 hours
// if you want to run the task immediately, set the 2nd parameter to 0
time.schedule(new CustomTask(), calendar.getTime(), TimeUnit.HOURS.toMillis(8));
}

Use Google Guava AbstractScheduledService as given below:
public class ScheduledExecutor extends AbstractScheduledService {
#Override
protected void runOneIteration() throws Exception {
System.out.println("Executing....");
}
#Override
protected Scheduler scheduler() {
return Scheduler.newFixedRateSchedule(0, 3, TimeUnit.SECONDS);
}
#Override
protected void startUp() {
System.out.println("StartUp Activity....");
}
#Override
protected void shutDown() {
System.out.println("Shutdown Activity...");
}
public static void main(String[] args) throws InterruptedException {
ScheduledExecutor se = new ScheduledExecutor();
se.startAsync();
Thread.sleep(15000);
se.stopAsync();
}
}
If you have more services like this, then registering all services in ServiceManager will be good as all services can be started and stopped together. Read here for more on ServiceManager.

If you want to stick with java.util.Timer, you can use it to schedule at large time intervals. You simply pass in the period you are shooting for. Check the documentation here.

Do something every one second
Timer timer = new Timer();
timer.schedule(new TimerTask() {
#Override
public void run() {
//code
}
}, 0, 1000);

These two classes can work together to schedule a periodic task:
Scheduled Task
import java.util.TimerTask;
import java.util.Date;
// Create a class extending TimerTask
public class ScheduledTask extends TimerTask {
Date now;
public void run() {
// Write code here that you want to execute periodically.
now = new Date(); // initialize date
System.out.println("Time is :" + now); // Display current time
}
}
Run Scheduled Task
import java.util.Timer;
public class SchedulerMain {
public static void main(String args[]) throws InterruptedException {
Timer time = new Timer(); // Instantiate Timer Object
ScheduledTask st = new ScheduledTask(); // Instantiate SheduledTask class
time.schedule(st, 0, 1000); // Create task repeating every 1 sec
//for demo only.
for (int i = 0; i <= 5; i++) {
System.out.println("Execution in Main Thread...." + i);
Thread.sleep(2000);
if (i == 5) {
System.out.println("Application Terminates");
System.exit(0);
}
}
}
}
Reference https://www.mkyong.com/java/how-to-run-a-task-periodically-in-java/

If your application is already using Spring framework, you have Scheduling built in

I use Spring Framework's feature. (spring-context jar or maven dependency).
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
#Component
public class ScheduledTaskRunner {
#Autowired
#Qualifier("TempFilesCleanerExecution")
private ScheduledTask tempDataCleanerExecution;
#Scheduled(fixedDelay = TempFilesCleanerExecution.INTERVAL_TO_RUN_TMP_CLEAN_MS /* 1000 */)
public void performCleanTempData() {
tempDataCleanerExecution.execute();
}
}
ScheduledTask is my own interface with my custom method execute, which I call as my scheduled task.

You can also use JobRunr, an easy to use and open-source Java Scheduler.
To schedule a Job every 8 hours using JobRunr, you would use the following code:
BackgroundJob.scheduleRecurrently(Duration.ofHours(8), () -> yourService.methodToRunEvery8Hours());
If you are using Spring Boot, Micronaut or Quarkus, you can also use the #Recurring annotation:
public class YourService {
#Recurring(interval="PT8H")
public void methodToRunEvery8Hours() {
// your business logic
}
}
JobRunr also comes with an embedded dashboard that allows you to follow-up on how your jobs are doing.

Have you tried Spring Scheduler using annotations ?
#Scheduled(cron = "0 0 0/8 ? * * *")
public void scheduledMethodNoReturnValue(){
//body can be another method call which returns some value.
}
you can do this with xml as well.
<task:scheduled-tasks>
<task:scheduled ref = "reference" method = "methodName" cron = "<cron expression here> -or- ${<cron expression from property files>}"
<task:scheduled-tasks>

my servlet contains this as a code how to keep this in scheduler if a user presses accept
if(bt.equals("accept")) {
ScheduledExecutorService scheduler=Executors.newScheduledThreadPool(1);
String lat=request.getParameter("latlocation");
String lng=request.getParameter("lnglocation");
requestingclass.updatelocation(lat,lng);
}

There is a ScheduledFuture class in java.util.concurrent, it may helps you.

How to set a timer but don't run repeatly

In my case I created a object and planned to release it after 20 minutes(accuracy is not necessary). I know by using java.util.Timer I can create a timer.But I just want it run once. After that,the timer should stop and been released too.
Is there any way just like setTimeOut() in javascript?
Thanks.

int numberOfMillisecondsInTheFuture = 10000; // 10 sec
Date timeToRun = new Date(System.currentTimeMillis()+numberOfMillisecondsInTheFuture);
Timer timer = new Timer();
timer.schedule(new TimerTask() {
public void run() {
// Task here ...
}
}, timeToRun);
Modify above so that you can schedule a job 20 minutes in future.

Use Timer::schedule(TimerTask, long) or look into the ScheduledThreadPoolExecutor or ScheduledExecutorService classes.

You can start a new thread and call sleep with the number of milliseconds to wait, then execute your instructions (on either thread). See http://download.oracle.com/javase/1.4.2/docs/api/java/lang/Thread.html for reference, and look at the various online thread tutorials if you need more help.

java.util.Timer has a cancel method in it:
http://download.oracle.com/javase/6/docs/api/java/util/Timer.html#cancel%28%29
However, as far as I know, in timer if you do not specify a period, scheduled task will run only once.

package com.stevej;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class StackOverflowMain {
public static void main(String[] args) {
ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1);
Runnable myAction = new Runnable() {
#Override
public void run() {
System.out.println("Hello (2 minutes into the future)");
}
};
executor.schedule(myAction, 2, TimeUnit.MINUTES);
}
}