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 C         


        

Answer 1

Yes, interface ApplicationContext doesn't have close() method, so I like to use class AbstractApplicationContext to use that close method explicitly and also here you can use your Spring Application configuration class using annotation instead of XML type.

AbstractApplicationContext context = new AnnotationConfigApplicationContext(SpringAppConfig.class);
Foo foo = context.getBean(Foo.class);

//do some work with foo

context.close();

your Resource leak: 'context' is never closed warning is gone now.

Answer 2

close() is not defined in ApplicationContext interface.

The only way to get rid of the warning safely is the following

ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(...);
try {
    [...]
} finally {
    ctx.close();
}

Or, in Java 7

try(ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(...)) {
    [...]
}

The basic difference is that since you instantiate the context explicitly (i.e. by use of new) you know the class you are instantiating, so you can define your variable accordingly.

If you were not instantiating the AppContext (i.e. using the one provided by Spring) then you couldn't close it.

Answer 3

If you are using the ClassPathXmlApplicationContext then you can use

((ClassPathXmlApplicationContext) context).close();

to close the resource leak problem.

If you are using the AbstractApplicationContext then you can cast this with close method.

((AbstractApplicationContext) context).close();

It depends on the type of context using in the application.

Answer 4

try this. you need to apply cast to close applicationcontext.

   ClassPathXmlApplicationContext ctx = null;
      try {
         ctx = new ClassPathXmlApplicationContext(...);
            [...]
             } finally {
              if (ctx != null)
                  ((AbstractApplicationContext) ctx).close();       
      }

Answer 5

Even I had the exact same warning, all I did was declare ApplicationContext outside the main function as private static and ta-da, problem fixed.

public class MainApp {
    private static ApplicationContext context;

    public static void main(String[] args) {
        context = new ClassPathXmlApplicationContext("Beans.xml");

        HelloWorld objA = (HelloWorld) context.getBean("helloWorld");

        objA.setMessage("I'm object A");
        objA.getMessage();

        HelloWorld objB = (HelloWorld) context.getBean("helloWorld");
        objB.getMessage();
    }
}