How to access same ClassPathXmlApplicationContext instance from 2 main methods - spring

Question

I've to write a quartz scheduler to run a job in Spring. I've to also add another function to pause the same job. This code is present inside a single standalone batch.
To trigger these 2 functions:
1. start the job
2. pause the job
I've written 2 classes with main() which does the execution.
The issue is when I trigger the main() for pauseJob, it starts the different applicationContext instead of using the same one. I've used a Singleton pattern for applicationContext initialization.
Singleton class for ApplicationContext initialization
public class AppContext {
private static ApplicationContext INSTANCE = null;
private AppContext() {
}
public static ApplicationContext getIntance() {
if (INSTANCE == null) {
String[] contexts = new String[] {"classpath:/applicationContext.xml"};
INSTANCE = new ClassPathXmlApplicationContext(contexts);
}
return INSTANCE;
}
}
Class to start the Job
public class StartJobQuartzMain {
public static void main(String[] args) throws Exception {
AppContext.getIntance();
}
}
Class to pause the job
public class PauseJobQuartzMain {
public static void main(String[] args) throws Exception {
((TestPauseJob) AppContext.getIntance().getBean("testPauseJob")).pauseJob();
}
}
Kindly guide me on how to fetch the same applicationContext instance in PauseJobQuartzMain.java. Thanks.

Answer 1

Making it a singleton has nothing to do with it (it is in a way required)... The two 'java' main classes will run independent of each other, as in, they are two different programs, with their own Java Virtual Machine, and will not be able to share your application context with each other.
You can use database or an external file (accessible by both) or something to achieve this...
Hope this helps...

Answer 2

You can’t do that from another main class because you run it definitely from a fresh JVM. So each of them has their own Singleton. You can consider to use some shared resource between two these apps: db, file, JMS queue finally etc. or you can call some managed operation over JMX. But two JVMs can’t share memory, especially Java objects, when application context is one of them.