What is meant by “application-context” in spring and how do you create one?

"application-context" in spring means nothing but it is core component of spring container in spring framework. Ideally we can say "application-context" one of the Spring Container in Spring Framework and other container is "bean-factory". The configuration for "application-context" is loaded by the one of concrete implementation of ApplicationContext interface.
The ApplicationContext is the central interface within a Spring Application for providing configuration information to the application. It is read-only at run time , but can be reloaded if necessary and supported by the application.


Major Responsibilities of "application-context" container

• It provides bean factory methods for accessing application components.
• It provides the ability to load file resources in a generic fashion.
• It provides the ability to publish event to register listeners
• It provide the ability to resolve to support internationalization.

Creating one "application-context"

• AnnotationConfigApplicationContext. Loads a Spring application context from one or moro Java-Based configuration classes.
  

  ApplicationContext context = new AnnotationConfigApplicationContext(JavaConfig.class;
  

• AnnotationConfigWebApplicationContext. Loads a Spring web application context from one or more Java-Based configuration classes.
  

  ApplicationContext context = new AnnotationConfigWebApplicationContext(JavaWebConfig.class;
  

• ClassPathXMLApplicationContext. Loads a context definition from one or more XML files located in the classpath
  

  ApplicationContext context = new ClassPathXMLApplicationContext("spingConfig.xml");
  

• FileSystemXMLApplicationContext. Loads a context definition from one or more XML files located in the filesystem.
  

  ApplicationContext context = new FileSystemXMLApplicationContext("c:/spingConfig.xml");
  

• XMLWebApplicationContext. Loads a context definition from one or more XML files contained in the web application.
  

  ApplicationContext context = new XMLWebApplicationContext("/WEB-INF/config/spingConfig.xml");
  

Accessing Application Context in the other classes:
You could also access the "application-context" container into other classes. You can implement ApplicationContextAware as in the following example:

public class AnotherClass implements ApplicationContextAware {

    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

}