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How to constantly check if time is up for auction site

I am working on a project where we are creating an auction site that works on a weekly basis. The plan is to start all auctions on Monday and end all on Friday.
So far I have figured out that I need a database that holds the start and end date so I can check to see how much time left and so. But I need to be able to constantly check and see if the time is up or not and I do not know how to proceed. What is the proper way to do this?
We are using Java8 with Spring and react as frontend.

two solution:
Use websocket, server set a timer which due at Friday, and once timer expired, send the event to client.
client side do timer also.

You have 3 layers in play here:
Frontend (React)
Backend (Java8/Spring app)
Database
Now you need to figure out how to propagate data between those layers.
Propagating from backend to frontend can be done using either polling or websockets.
Propagating from database to backend can be done using either polling or database triggers.
I'd personally connect React with Spring App via websockets. Then I'd have some background task polling the database and pushing the discovered changes to connected websocket clients.
Here is Springs own tutorial on websockets https://spring.io/guides/gs/messaging-stomp-websocket/

I think you are looking for a pull model. Basically your Java application needs to pull the end date from database at certain intervals. You can write a cron job for that.Quartz cron is one of the popular Java based frameworks out there http://www.quartz-scheduler.org/documentation/quartz-2.3.0/tutorials/crontrigger.html . It handles distributed system also. So if your application is having multiple instances, Quartz can cover it for you.
Another variant in pull model, you can read the entry with end dates in JVM local cache or some other cache(Redis, Memcache) & run a cron on that. But you have to maintain cache consistency with database.
Which one you choose depends on your business use case(how frequently end date changes, how frequently you need to check for end dates etc.).
Other option was to go for push model. But push model won't work with traditional databases for this case.

Possible option - is to extend org.springframework.web.servlet.handler.HandlerInterceptorAdapter
And write logic of checking current time against your time range in this class - with throwing of an exception if check fails.
Potential optimization - cache values from DB (at least for some time, for example - 15 minutes - as it will help to decrease number of actual calls to the database.

Scheduler in a java spring boot microservice

We have a microservice written using Spring boot which has its own NoSQL datastore. We are working on functionality whereby we want to delete some old data (in magnitude of 0.5 million documents) and want to do it on a regular basis(once a day) based on presence of records of particular type in data store.
Is having a scheduler which runs once everyday and does the deletion, a correct approach for it ? Also since its a microservice and several instances of it will be running, how do we control that this scheduler runs on only 1 instance ?

There are multiple options I can think of now:
If there is a single instance of micro-service deployed, you can use something like quartz to time the job.
Create a RESTful API for cleanup, invoke it using a script, please refer to https://stackoverflow.com/a/15090893/2817980 for example. This will make sure that only one instance of the service works on cleanup.
If there is a master-slave replica, ask the master to allocate to only 1 instance
Create a scheduled job using something like quartz and then check if the job already taken up by some other scheduler in zookeeper/redis/db or any other storage.
I can discuss more on this.

Real time data consumption from mysql

I have a use case in which my data is present in Mysql.
For each new row insert in Mysql, I have to perform analytics for the new data.
How I am currently solving this problem is:
My application is a Spring-boot application, in which I have used Scheduler which checks for new row entered in the database after every 2 seconds.
The problem with the current approach is:
Even if there is no new data available in Mysql table, Scheduler fires MySQL query to check if new data available or not.
One way to solve this type of problem in any SQL database in Triggers .
But till now I am not successful in creating Mysql triggers which can call Java-based Spring application or a simple java application.
My question is :
Is their any better way to solve my above use-case? Even I am open to change to another storage (database) system if they are built for this type of use-case.

This fundamentally sounds like an architecture issue. You're essentially using a database as an API which, as you can see, causes all kinds of issues. Ideally, this db would be wrapped in a service that can manage the notification of systems that need to be notified. Let's look at a few different options going forward.
Continue to poll
You didn't outline what the actual issue is with your current polling approach. Is running the job when it's not needed causing an issue of some kind? I'd be a proponent for just leaving it unless you're interested in making a larger change.
Database Trigger
While I'm unaware of a way to launch a java process via a db trigger, you can do an HTTP POST from one. With that in mind, you can have your batch job staged in a web app that uses a POST to launch the job when the trigger fires.
Wrap existing datastore in a service
This is, IMHO, the best option. This allows there to be a system of record that provides an API that can be versioned, etc. This would allow any logic around who to notify would also be encapsulated into this service.
Replace data store with something that allows for better notifications
Without any real information on what the data being store is, it's hard to say how practical this is. But using something as Apache Kafka or Apache Geode would both be options that provide the ability to be notified when new data is persisted (Kafka by listening to the topic, Geode via a continuous query).
For the record, I'd advocate for the wrapping of the existing database in a service. That service would be the only way into the db and take on responsibility for any notifications required.

Fast Multithreaded Online Processing Application Framework Suggestions

I am looking for a pattern and/or framework which can model the following problem in an easily configurable way.
Every say 3 minutes, I needs to have a set of jobs kick off in a web application context that will concurrently hit web services to obtain the latest version of data, and push it off to a database. The problem is the database will be being heavily used to read the data from to do tons of complex calculations on the data. We are currently using spring so I have been looking at Spring Batch to run this process does anyone have any suggestions/patterns/examples of using Spring or other technologies of a similar system?

We have used ServletContextlisteners to kick off TimerTasks in our web applications when we needed processes to run repeatedly. The ServletContextListener kicks off when the app server starts the application or when the application is restarted. Then the timer tasks act like a separate thread that repeats your code for the specified period of time.
ServletContextListener
http://www.javabeat.net/examples/2009/02/26/servletcontextlistener-example/
TimerTask
http://enos.itcollege.ee/~jpoial/docs/tutorial/essential/threads/timer.html

Is refactoring the job out of the web application and into a standalone app a possibility?
That way you could stick the batch job onto a separate batch server (so that the extra load of the batch job wouldn't impact your web application), which then calls the web services and updates the database. The job can then be kicked off using something like cron or Autosys.
We're using Spring-Batch for exactly this purpose.
The database design would also depend on what the batched data is used for. If it is for reporting purposes, I would recommend separating the operational database from the reporting database, using a database link to obtain the required data from the operational database into the reporting database and then running the complex queries on the reporting database. That way the load is shifted off the operational database.

I think it's worth also looking into frameworks like camel-integration. Also take a look at the so called Enterprise Integration Patterns. Check the catalog - it might provide you with some useful vocabulary to think about the scaling/scheduling problem at hand.
The framework itself integrates really well with Spring.

Running scheduled methods on tomcat

I am trying to set up a method that will be automatically run by the server at a specific time. For instance, a method that sends out emails to contacts every Friday at 9.00 am. I have seen methods that are run when the server is first started and was wondering if what I want to do is possible. If it is possible, can someone point me to where I can start reading up how to do this. Any help will be highly appreciated.

There is an excellent library quartz which can help you create scheduled tasks within your application. See e.g., the Job Scheduling in Java guide by o'reilly.

If you really want to do it manually (and not use specific tools like Quartz), you could use a Timer, which would be created when the application is deployed and canceled when the application is destroyed, using a ServletContextListener declared in your web.xml.
Be prepared for additional complexity if your application is clustered on multiple servers, though.

I also recommend using Quartz as Johan already suggested, it is a well-established solution for job scheduling in Java applications and also allows for central job storage in a database and clustering of multiple Tomcat instances.
In case your web application uses the Spring Framework, you could instead use the built-in scheduling support instead.