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Without further context, it is really impossible to help you. Which Liferay version? What did you deploy?
There is probably some error in your code or in the configuration, but it is impossible to help you without seeing the source code.

I have prepared a demo portlet with gravel to start with. However, while trying to publish it on the web portal, the portlet doesn't get deployed. 
 

On top of what Christoph said: Please don't post textual content as images. That takes space, requires extra clicks, can't be copied, isn't visible without clicking, etc etc.
Please rephrase your question with steps to reproduce - because the portlet that I wrote recently compiles and deploys just fine - I can't reproduce your problem with my portlet.