how to make sure single guava service manager instance per jvm?

Question

Singleton pattern allows to contain one instance per application thread.

How can I make sure only single instance of guava Service Manager is running per JVM ? So when ever it launches a new seperate entry java thread can check whether the service manager is running.

Answer 1

Why do you think that simply not creating multiple instances wouldn't work? Implement a ServiceManagerProvider as a singleton and use only serviceManagerProvider.get() for accessing the Service Manager.

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Consider using Dependency Injection instead of the singleton (anti-)pattern:

@Singleton
public class ServiceManagerProvider implements Provider<ServiceManager> {
    private final ServiceManager serviceManager = ...

    @Overrride
    public ServiceManager get() {
        return serviceManager;
    }
}

Here, you get a single instance per injector, which is exactly what you (should) want.