Doc: Lifecycle (not SmartLifecycle) beans not started at refresh() time [SPR-12855]

[spring-projects-issues]

Edward Sargisson opened SPR-12855 and commented

The docs say that a top-level bean may implement Lifecycle and have its start method called at startup.

Using such a bean with XmlWebApplicationContext does not have its start method called. Only a bean that implements SmartLifecycle does.

The defects appears to be that FrameworkServlet.configureAndRefreshWebApplicationContext only calls refresh on the web application context. It only ever calls refresh(). This means that the DefaultLifecycleProcessor ends up calling startBeans(autoStartupOnly=true).

In startBeans the following check means that only SmartLifecycle beans are added to the phases collection (and then started).
if (!autoStartupOnly || (bean instanceof SmartLifecycle && ((SmartLifecycle) bean).isAutoStartup()))

I found this in 4.0.5 but a check of the source on github suggests it's still there.

If there are other code paths that result in DefaultLifecycleProcessor.start() being called I couldn't find them.

Workaround

Implement SmartLifecycle instead of Lifecycle.

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Affects: 3.2.13, 4.0.5

Backported to: 3.2.14

[spring-projects-issues]

Juergen Hoeller commented

This is in fact as designed: Regular Lifecycle beans do get ConfigurableApplicationContext.start() calls propagated but are not auto-started by ConfigurableApplicationContext.refresh(). Just SmartLifecycle beans are able to indicate such an auto-startup and are also able to influence the startup order through their phase.

In other words, for regular Lifecycle beans, an ApplicationContext just acts as a propagator of explicit start/stop calls but doesn't do any special treatment beyond that.

All of that said, the documentation isn't as clear as it should be here, so I'll turn this into a documentation task. Thanks for raising this!

Juergen

[spring-projects-issues]

Edward Sargisson commented

Juergen: Thanks for looking at this.
Part of my point was that when I went tracking back through the source to see what I was missing I couldn't find a .start() call for the code path. I could only find refresh().
This might have been because the Eclipse Search References got confused so perhaps you could point out the code path it's supposed to use when starting a webapp?

[spring-projects-issues]

Juergen Hoeller commented

There are two distinct code paths through DefaultLifecycleProcessor: in the refresh phase, handling auto-startups; and through its own implementation of the Lifecycle interface, propagating the start/stop/restart calls to all lifecycle beans. The latter is typically triggered through AbstractApplicationContext's implementation of the Lifecycle interface, for programmatic starting/stopping of the entire context.

Hope that helps,

Juergen