java.io.FileNotFoundException: class path resource cannot be opened because it does not exist

What you put directly under src/main/java is in the default package, at the root of the classpath. It's the same for resources put under src/main/resources: they end up at the root of the classpath.

So the path of the resource is app-context.xml, not main/resources/app-context.xml.

We can also try this solution

ApplicationContext ctx = new ClassPathXmlApplicationContext("classpath*:app-context.xml");

in this the spring automatically finds the class in the class path itself

Try this:

ApplicationContext context = new ClassPathXmlApplicationContext("app-context.xml");