java - Spring ApplicationContext - Resource leak: 'context' is never closed

Question

In a spring MVC application, I initialize a variable in one of the service classes using the following approach:

ApplicationContext context = 
         new ClassPathXmlApplicationContext("META-INF/userLibrary.xml");
service = context.getBean(UserLibrary.class);

The UserLibrary is a 3rd party utility which I am using in my application. The above code generates a warning for the 'context' variable. The warning is shown below:

Resource leak: 'context' is never closed

I don't understand the warning. As the application is a Spring MVC application, I can't really close/destroy the context as I refer to the service while the application is running. What exactly is the warning trying to tell me?

Answer 1

Since the app context is a ResourceLoader (i.e. I/O operations) it consumes resources that need to be freed at some point. It is also an extension of AbstractApplicationContext which implements Closable. Thus, it's got a close() method and can be used in a try-with-resources statement.

try (ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("META-INF/userLibrary.xml")) {
  service = context.getBean(UserLibrary.class);
}

Whether you actually need to create this context is a different question (you linked to it), I'm not gonna comment on that.

It's true that the context is closed implicitly when the application is stopped but that's not good enough. Eclipse is right, you need to take measures to close it manually for other cases in order to avoid classloader leaks.