This probably indicates a problem during initialization of the platform.
I would recommend reviewing your startup log to confirm there are absolutely no issues, it could very well be that your startup flow is holding the app back.
You probably want to double check that you don't have any compile and class loader errors, so make sure you clean the deployment directory, and re-deploy/start the application. Also check eclipse just to make sure that it compiles properly.
It could also be that the platform is busy doing something and doesn't have time to respond. The best way to confirm where exactly the platform stops, and if anything even runs is to start the application with TRACE logging enabled.
This should print a huge amount of messages, but after all startup actions it should be readable. If the platform freezes on any of the steps you can see it here. (The most likely log nodes to check are 'Microflowengine', 'Connectionbus_retrieve/update/mapping' and 'Core'